List of basic astronomy topics
Encyclopedia
Astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
– studies the universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
beyond Earth, including its formation and development
Physical cosmology
Physical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
, and the evolution, physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
, meteorology
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...
, and motion
Motion (physics)
In physics, motion is a change in position of an object with respect to time. Change in action is the result of an unbalanced force. Motion is typically described in terms of velocity, acceleration, displacement and time . An object's velocity cannot change unless it is acted upon by a force, as...
of celestial objects
Astronomical object
Astronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe. The term astronomical object is sometimes used interchangeably with astronomical body...
(such as galaxies
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
, planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s, etc.) and phenomena
Phenomenon
A phenomenon , plural phenomena, is any observable occurrence. Phenomena are often, but not always, understood as 'appearances' or 'experiences'...
that originate outside the atmosphere of Earth (such as the cosmic background radiation
Cosmic microwave background radiation
In cosmology, cosmic microwave background radiation is thermal radiation filling the observable universe almost uniformly....
).
Nature of astronomy
Astronomy can be described as all of the following:- An academic disciplineAcademic disciplineAn academic discipline, or field of study, is a branch of knowledge that is taught and researched at the college or university level. Disciplines are defined , and recognized by the academic journals in which research is published, and the learned societies and academic departments or faculties to...
: one with academic departments, curricula and degrees; national and international societies; and specialized journals. - A scientific field (a branch of scienceScienceScience is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe...
) – widely-recognized category of specialized expertise within science, and typically embodies its own terminology and nomenclature. Such a field will usually be represented by one or more scientific journals, where peer reviewed research is published.- A natural scienceNatural scienceThe natural sciences are branches of science that seek to elucidate the rules that govern the natural world by using empirical and scientific methods...
– one that seeks to elucidate the rules that govern the naturalNatureNature, in the broadest sense, is equivalent to the natural world, physical world, or material world. "Nature" refers to the phenomena of the physical world, and also to life in general...
world using empiricalEmpirical methodThe empirical method is generally taken to mean the approach of using a collection of data to base a theory or derive a conclusion in science...
and scientific methodScientific methodScientific method refers to a body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of...
s.- A branch or field of space scienceSpace scienceThe term space science may mean:* The study of issues specifically related to space travel and space exploration, including space medicine.* Science performed in outer space ....
–
- A branch or field of space science
- A natural science
Branches of astronomy
- AstrophysicsAstrophysicsAstrophysics is the branch of astronomy that deals with the physics of the universe, including the physical properties of celestial objects, as well as their interactions and behavior...
– branch of astronomyAstronomyAstronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...
that deals with the physicsPhysicsPhysics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
of the universeUniverseThe Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
, including the physical properties of celestial objectAstronomical objectAstronomical objects or celestial objects are naturally occurring physical entities, associations or structures that current science has demonstrated to exist in the observable universe. The term astronomical object is sometimes used interchangeably with astronomical body...
s, as well as their interactions and behavior. Among the objects studied are galaxiesGalaxyA galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
, starStarA star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s, planetPlanetA planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s, exoplanets, the interstellar mediumInterstellar mediumIn astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
and the cosmic microwave background; and the properties examined include luminosityLuminosityLuminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...
, densityDensityThe mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
, temperatureTemperatureTemperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, and chemicalChemistryChemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....
composition. The subdisciplines of theoretical astrophysics are:- AstrobiologyAstrobiologyAstrobiology is the study of the origin, evolution, distribution, and future of life in the universe. This interdisciplinary field encompasses the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry,...
– studies the advent and evolutionEvolutionEvolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
of biological systemBiological systemIn biology, a biological system is a group of organs that work together to perform a certain task. Common systems, such as those present in mammals and other animals, seen in human anatomy, are those such as the circulatory system, the respiratory system, the nervous system, etc.A group of systems...
s in the universe. - Compact objects – this subdiscipline studies very dense matter in white dwarfWhite dwarfA white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
s and neutron starNeutron starA neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
s and their effects on environments including accretionAccretion (astrophysics)In astrophysics, the term accretion is used for at least two distinct processes.The first and most common is the growth of a massive object by gravitationally attracting more matter, typically gaseous matter in an accretion disc. Accretion discs are common around smaller stars or stellar remnants...
. - Exoplanet studies – various planets outside of the Solar System
- Physical cosmologyPhysical cosmologyPhysical cosmology, as a branch of astronomy, is the study of the largest-scale structures and dynamics of the universe and is concerned with fundamental questions about its formation and evolution. For most of human history, it was a branch of metaphysics and religion...
– origin and evolution of the universe as a whole. The study of cosmology is theoretical astrophysics at its largest scale. - Galactic astronomyGalactic astronomyGalactic astronomy is the study of our own Milky Way galaxy and all its contents. This is in contrast to extragalactic astronomy, which is the study of everything outside our galaxy, including all other galaxies....
– deals with the structure and components of our galaxy and of other galaxies. - High energy astrophysics – studies phenomena occurring at high energies including active galactic nuclei, supernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
e, gamma-ray bursts, quasarQuasarA quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
s, and shocks. - Interstellar astrophysics – study of the interstellar mediumInterstellar mediumIn astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space...
, intergalactic medium and dustDustDust consists of particles in the atmosphere that arise from various sources such as soil dust lifted up by wind , volcanic eruptions, and pollution...
. - Extragalactic astronomyExtragalactic astronomyExtragalactic astronomy is the branch of astronomy concerned with objects outside our own Milky Way Galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy, the next level of galactic astronomy....
– study of objects (mainly galaxies) outside our galaxy, including Galaxy formation and evolutionGalaxy formation and evolutionThe study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby...
. - Stellar astronomy – concerned with Star formationStar formationStar formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
, physical properties, main sequenceMain sequenceThe main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
life span, variabilityVariable starA star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
, stellar evolutionStellar evolutionStellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...
and extinction. - Plasma astrophysics – studies properties of plasmaPlasma (physics)In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
in outer space. - Relativistic astrophysics – studies effects of special relativitySpecial relativitySpecial relativity is the physical theory of measurement in an inertial frame of reference proposed in 1905 by Albert Einstein in the paper "On the Electrodynamics of Moving Bodies".It generalizes Galileo's...
and general relativityGeneral relativityGeneral relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...
in astrophysical contexts including gravitational waves, gravitational lensGravitational lensA gravitational lens refers to a distribution of matter between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer...
ing and black holeBlack holeA black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
s.
- Astrobiology
- Planetary SciencePlanetary sciencePlanetary science is the scientific study of planets , moons, and planetary systems, in particular those of the Solar System and the processes that form them. It studies objects ranging in size from micrometeoroids to gas giants, aiming to determine their composition, dynamics, formation,...
– study of the planets of the Solar SystemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
.- Atmospheric science – study of atmospheres and weather.
- Planetary formation – formation of planets and moons in the context of the formation and evolution of the Solar SystemFormation and evolution of the Solar SystemThe formation and evolution of the Solar System is estimated to have begun 4.568 billion years ago with the gravitational collapse of a small part of a giant molecular cloud...
. - Planetary rings – dynamics, stability, and composition of planetary rings
- Solar physicsSolar physicsFor the physics journal, see Solar Physics Solar physics is the study of our Sun. It is a branch of astrophysics that specializes in exploiting and explaining the detailed measurements that are possible only for our closest star...
– Sun and its interaction with the remainder of the Solar System and interstellar space. - MagnetosphereMagnetosphereA magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
s – magnetic fields of planets and moons - Planetary surfaces – surface geology of planets and moons
- Planetary interiors – interior composition of planets and moons
- Small Solar System bodies – smallest gravitationally bound bodies, including asteroidAsteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s, cometCometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s, and Kuiper belt objects.
The subdisciplines of observational astronomy
Observational astronomy
Observational astronomy is a division of the astronomical science that is concerned with getting data, in contrast with theoretical astrophysics which is mainly concerned with finding out the measurable implications of physical models...
are generally made by the specifications of the detectors:
- Radio astronomyRadio astronomyRadio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The initial detection of radio waves from an astronomical object was made in the 1930s, when Karl Jansky observed radiation coming from the Milky Way. Subsequent observations have identified a number of...
– Above 300 micrometres - Submillimetre astronomySubmillimetre astronomySubmillimetre astronomy or submillimeter astronomy is the branch of observational astronomy that is conducted at submillimetre wavelengths of the electromagnetic spectrum. Astronomers place the submillimetre waveband between the far-infrared and microwave wavebands, typically taken to be between a...
– 200 µm to 1 mm - Infrared astronomyInfrared astronomyInfrared astronomy is the branch of astronomy and astrophysics that studies astronomical objects visible in infrared radiation. The wavelength of infrared light ranges from 0.75 to 300 micrometers...
– 0.7–350 µm - Optical astronomy – 380–750 nm
- Ultraviolet astronomy – 10–320 nm
- X-ray astronomyX-ray astronomyX-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects. X-radiation is absorbed by the Earth's atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and...
– 0.01–10 nm - Gamma-ray astronomyGamma-ray astronomyGamma-ray astronomy is the astronomical study of the cosmos with gamma rays. Gamma-rays are the most energetic form of "light" that travel across the universe, and gamma-rays thus have the smallest wavelength of any wave in the electromagnetic spectrum.Gamma-rays are created by celestial events...
– Below 0.01 nm - Cosmic ray astronomy – Cosmic rayCosmic rayCosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
s, including plasma - Neutrino astronomyNeutrino astronomyNeutrino astronomy is the branch of astronomy that observes astronomical objects with neutrino detectors in special observatories. Nuclear reactions in stars and supernova explosions produce very large numbers of neutrinos, a very few of which may be detected by a neutrino telescope...
– NeutrinoNeutrinoA neutrino is an electrically neutral, weakly interacting elementary subatomic particle with a half-integer spin, chirality and a disputed but small non-zero mass. It is able to pass through ordinary matter almost unaffected...
s - Gravitational wave astronomyGravitational wave astronomyGravitational Wave Astronomy is an emerging branch of observational astronomy which aims to use gravitational waves to collect observational data about objects such as neutron stars and black holes, about events such as supernovae and about the early universe shortly after the big bang...
– GravitonGravitonIn physics, the graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory. If it exists, the graviton must be massless and must have a spin of 2...
s
General techniques for astronomical research are also convenient ways of dividing the field:
- PhotometryPhotometry (astronomy)Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...
– study of how bright celestial objects are when passed through different filters - SpectroscopySpectroscopySpectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
– study of the spectra of astronomical objects - AstrometryAstrometryAstrometry is the branch of astronomy that involves precise measurements of the positions and movements of stars and other celestial bodies. The information obtained by astrometric measurements provides information on the kinematics and physical origin of our Solar System and our Galaxy, the Milky...
– study of the position of objects in the sky and their changes of position. Defines the system of coordinates used and the kinematicsKinematicsKinematics is the branch of classical mechanics that describes the motion of bodies and systems without consideration of the forces that cause the motion....
of objects in our galaxy.
Other disciplines that may be considered part of astronomy:
- ArchaeoastronomyArchaeoastronomyArchaeoastronomy is the study of how people in the past "have understood the phenomena in the sky how they used phenomena in the sky and what role the sky played in their cultures." Clive Ruggles argues it is misleading to consider archaeoastronomy to be the study of ancient astronomy, as modern...
– - AstrochemistryAstrochemistryAstrochemistry is the study of the abundance and reactions of chemical elements and molecules in the universe, and their interaction with radiation. The discipline is an overlap of astronomy and chemistry. The word "astrochemistry" may be applied to both the Solar System and the interstellar medium...
–
History of astronomy
- Main article: History of astronomyHistory of astronomyAstronomy is the oldest of the natural sciences, dating back to antiquity, with its origins in the religious, mythological, and astrological practices of pre-history: vestiges of these are still found in astrology, a discipline long interwoven with public and governmental astronomy, and not...
- ArchaeoastronomyArchaeoastronomyArchaeoastronomy is the study of how people in the past "have understood the phenomena in the sky how they used phenomena in the sky and what role the sky played in their cultures." Clive Ruggles argues it is misleading to consider archaeoastronomy to be the study of ancient astronomy, as modern...
– - Babylonian astronomy –
- Chinese astronomyChinese astronomyAstronomy in China has a very long history, with historians considering that "they [the Chinese] were the most persistent and accurate observers of celestial phenomena anywhere in the world before the Arabs."...
– - Egyptian astronomyEgyptian astronomyEgyptian astronomy begins in prehistoric times, in the Predynastic Period. In the 5th millennium BCE, the stone circles at Nabta Playa may have made use of astronomical alignments...
– - Greek astronomyGreek astronomyGreek astronomy is astronomy written in the Greek language in classical antiquity. Greek astronomy is understood to include the ancient Greek, Hellenistic, Greco-Roman, and Late Antiquity eras. It is not limited geographically to Greece or to ethnic Greeks, as the Greek language had become the...
– - Hebrew astronomyHebrew astronomyHebrew astronomy refers to any astronomy written in Hebrew or by Hebrew speakers, or translated into Hebrew. It also includes an unusual type of literature from the Middle Ages: works written in Arabic but transcribed in the Hebrew alphabet...
– - Indian astronomy –
- Islamic astronomyIslamic astronomyIslamic astronomy or Arabic astronomy comprises the astronomical developments made in the Islamic world, particularly during the Islamic Golden Age , and mostly written in the Arabic language. These developments mostly took place in the Middle East, Central Asia, Al-Andalus, and North Africa, and...
– - Russian astronomy –
- Science in Medieval Western Europe –
Basic astronomical phenomena
- AtmosphereAtmosphereAn atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...
– - Celestial poleCelestial poleThe north and south celestial poles are the two imaginary points in the sky where the Earth's axis of rotation, indefinitely extended, intersects the imaginary rotating sphere of stars called the celestial sphere...
– - EclipseEclipseAn eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer...
– - EclipticEclipticThe ecliptic is the plane of the earth's orbit around the sun. In more accurate terms, it is the intersection of the celestial sphere with the ecliptic plane, which is the geometric plane containing the mean orbit of the Earth around the Sun...
– - Cosmic rays –
- Kepler's laws –
- Doppler effectDoppler effectThe Doppler effect , named after Austrian physicist Christian Doppler who proposed it in 1842 in Prague, is the change in frequency of a wave for an observer moving relative to the source of the wave. It is commonly heard when a vehicle sounding a siren or horn approaches, passes, and recedes from...
– - NutationNutationNutation is a rocking, swaying, or nodding motion in the axis of rotation of a largely axially symmetric object, such as a gyroscope, planet, or bullet in flight, or as an intended behavior of a mechanism...
– - OrbitOrbitIn physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
– - PerturbationPerturbation (astronomy)Perturbation is a term used in astronomy in connection with descriptions of the complex motion of a massive body which is subject to appreciable gravitational effects from more than one other massive body....
– - Precession –
- Proper motionProper motionThe proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
– - RedshiftRedshiftIn physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...
– - Solar eclipseSolar eclipseAs seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...
– - Tides –
- ZodiacZodiacIn astronomy, the zodiac is a circle of twelve 30° divisions of celestial longitude which are centred upon the ecliptic: the apparent path of the Sun across the celestial sphere over the course of the year...
–
Instruments, measurement and units
- Radio telescopeRadio telescopeA radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
– - TelescopeTelescopeA telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...
– - CalendarCalendarA calendar is a system of organizing days for social, religious, commercial, or administrative purposes. This is done by giving names to periods of time, typically days, weeks, months, and years. The name given to each day is known as a date. Periods in a calendar are usually, though not...
– - Astronomical UnitAstronomical unitAn astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....
– - Celestial coordinates –
- ParsecParsecThe parsec is a unit of length used in astronomy. It is about 3.26 light-years, or just under 31 trillion kilometres ....
– - PrecessionPrecessionPrecession is a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
– - Celestial mechanicsCelestial mechanicsCelestial mechanics is the branch of astronomy that deals with the motions of celestial objects. The field applies principles of physics, historically classical mechanics, to astronomical objects such as stars and planets to produce ephemeris data. Orbital mechanics is a subfield which focuses on...
– - Solar timeSolar timeSolar time is a reckoning of the passage of time based on the Sun's position in the sky. The fundamental unit of solar time is the day. Two types of solar time are apparent solar time and mean solar time .-Introduction:...
– - Sidereal timeSidereal timeSidereal time is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky...
–
Solar system
- Solar SystemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
- Geology of solar terrestrial planetsGeology of solar terrestrial planetsThe geology of solar terrestrial planets mainly deals with the geological aspects of four planets of the Solar system namely, Mercury, Venus, Earth, and Mars and one terrestrial dwarf planet, Ceres...
- List of solar system objects
- List of solar system objects by size
- Galilean satellites –
- Halley's comet –
Sun
SunSun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
–
- Location
- Milky WayMilky WayThe Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
- Solar systemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
- Solar system
- Milky Way
- Stellar classificationStellar classificationIn astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
: Stellar classification#Class G - Internal structure
- Standard Solar ModelStandard Solar ModelThe Standard Solar Model refers to a mathematical treatment of the Sun as a spherical ball of gas...
- Solar coreSolar coreThe core of the Sun is considered to extend from the center to about 0.2 to 0.25 solar radius. It is the hottest part of the Sun and of the Solar System. It has a density of up to 150 g/cm³ and a temperature of close to 15,000,000 kelvin...
- Radiation zoneRadiation zoneThe radiation zone is the middle zone in the Sun's interior. Energy travels out of the core into the radiation zone. Energy that travels through the radiation zone is in the form of electromagnetic radiation. The radiation zone is so dense that the waves bounce around...
- Convection zoneConvection zoneThe convection zone of a star is the range of radii in which energy is transported primarily by convection. In the radiation zone, energy is transported by radiation...
- Standard Solar Model
- Stellar atmosphereStellar atmosphereThe stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. It is divided into several regions of distinct character:...
- PhotospherePhotosphereThe photosphere of an astronomical object is the region from which externally received light originates. The term itself is derived from Ancient Greek roots, φῶς, φωτός/phos, photos meaning "light" and σφαῖρα/sphaira meaning "sphere", in reference to the fact that it is a spheric surface perceived...
- SupergranulationSupergranulationSupergranulation is a particular pattern on the Sun's surface. It was discovered in the 1950s by A.B.Hart using Doppler velocity measurements showing horizontal flows on the photosphere ....
- GranuleGranule (solar physics)Granules on the photosphere of the Sun are caused by convection currents of plasma within the Sun's convective zone. The grainy appearance of the solar photosphere is produced by the tops of these convective cells and is called granulation.The rising part of the granules is located in the center...
- FaculaFaculaA facula , Latin for "little torch", is literally a "bright spot." It is used in planetary nomenclature for naming certain surface features of planets and moons, and is also a type of surface phenomenon on the Sun....
e - SunspotSunspotSunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
- Supergranulation
- ChromosphereChromosphereThe chromosphere is a thin layer of the Sun's atmosphere just above the photosphere, roughly 2,000 kilometers deep....
- PlagePlage (astronomy)A plage is a bright region in the chromosphere of the Sun, typically found in regions of the chromosphere near sunspots.The term itself is poetically taken from the French word for "beach." The plage regions map closely to the faculae in the photosphere below, but the latter have much smaller...
- SpiculeSpicule (solar physics)In solar physics, a spicule is a dynamic jet of about 500 km diameter in the chromosphere of the Sun. It moves upwards at about 20 km/s from the photosphere...
- Moreton waveMoreton waveA Moreton wave is the chromospheric signature of a large-scale solar coronal shock wave. Described as a kind of solar 'tsunami', they are generated by solar flares. They are named for American astronomer Gail Moreton, an observer at the Lockheed Solar Observatory in Burbank who spotted them in 1959...
- Plage
- CoronaCoronaA corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...
- Solar transition regionSolar transition regionThe solar transition region is a region of the Sun's atmosphere, between the chromosphere and corona. It is visible from space using telescopes that can sense ultraviolet...
- Coronal hole
- Coronal loopCoronal loopCoronal loops form the basic structure of the lower corona and transition region of the Sun. These highly structured and elegant loops are a direct consequence of the twisted solar magnetic flux within the solar body. The population of coronal loops can be directly linked with the solar cycle; it...
- Coronal mass ejectionCoronal mass ejectionA coronal mass ejection is a massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space....
- Solar prominenceSolar prominenceA prominence is a large, bright feature extending outward from the Sun's surface, often in a loop shape. Prominences are anchored to the Sun's surface in the photosphere, and extend outwards into the Sun's corona...
- Helmet streamerHelmet streamerHelmet streamers are bright loop-like structures which develop over active regions on the sun. They are closed magnetic loops which connect regions of opposite magnetic polarity. Electrons are captured in these loops, and cause them to glow very brightly. The solar wind elongates these loops to...
- Solar transition region
- Photosphere
- Solar variationSolar variationSolar variation is the change in the amount of radiation emitted by the Sun and in its spectral distribution over years to millennia. These variations have periodic components, the main one being the approximately 11-year solar cycle . The changes also have aperiodic fluctuations...
- Solar cycleSolar cycleThe solar cycle, or the solar magnetic activity cycle, is a periodic change in the amount of irradiation from the Sun that is experienced on Earth. It has a period of about 11 years, and is one component of solar variation, the other being aperiodic fluctuations. Solar variation causes changes in...
- Solar maximumSolar maximumSolar maximum or solar max is the period of greatest solar activity in the solar cycle of the sun. During solar maximum, sunspots appear....
- Solar minimumSolar minimumSolar minimum is the period of least solar activity in the solar cycle of the sun. During this time, sunspot and solar flare activity diminishes, and often does not occur for days at a time...
- Wolf numberWolf numberThe Wolf number is a quantity that measures the number of sunspots and groups of sunspots present on the surface of the sun....
- Solar flareSolar flareA solar flare is a sudden brightening observed over the Sun surface or the solar limb, which is interpreted as a large energy release of up to 6 × 1025 joules of energy . The flare ejects clouds of electrons, ions, and atoms through the corona into space. These clouds typically reach Earth a day...
- HelioseismologyHelioseismologyHelioseismology is the study of the propagation of wave oscillations, particularly acoustic pressure waves, in the Sun. Unlike seismic waves on Earth, solar waves have practically no shear component . Solar pressure waves are believed to be generated by the turbulence in the convection zone near...
- Solar cycle
- HeliosphereHeliosphereThe heliosphere is a bubble in space "blown" into the interstellar medium by the solar wind. Although electrically neutral atoms from interstellar volume can penetrate this bubble, virtually all of the material in the heliosphere emanates from the Sun itself...
- Solar windSolar windThe solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 1.5 and 10 keV. The stream of particles varies in temperature and speed over time...
- Heliospheric current sheetHeliospheric current sheetThe heliospheric current sheet is the surface within the Solar System where the polarity of the Sun's magnetic field changes from north to south. This field extends throughout the Sun's equatorial plane in the heliosphere. The shape of the current sheet results from the influence of the Sun's...
- Heliospheric current sheet
- Heliosphere#Termination shock
- Heliosphere#Heliosheath
- Heliosphere#Heliopause
- Bow shockBow shockA bow shock is the area between a magnetosphere and an ambient medium. For stars, this is typically the boundary between their stellar wind and the interstellar medium....
- Solar wind
- Related phenomena
- Solar dynamoSolar dynamoThe solar dynamo is the physical process that generates the Sun's magnetic field. The Sun is permeated by an overall dipole magnetic field, as are many other celestial bodies such as the Earth. The dipole field is produced by a circular electric current flowing deep within the star, following...
- Solar eclipseSolar eclipseAs seen from the Earth, a solar eclipse occurs when the Moon passes between the Sun and the Earth, and the Moon fully or partially blocks the Sun as viewed from a location on Earth. This can happen only during a new moon, when the Sun and the Moon are in conjunction as seen from Earth. At least...
- SunlightSunlightSunlight, in the broad sense, is the total frequency spectrum of electromagnetic radiation given off by the Sun. On Earth, sunlight is filtered through the Earth's atmosphere, and solar radiation is obvious as daylight when the Sun is above the horizon.When the direct solar radiation is not blocked...
- Solar energy
- Solar dynamo
- Equipment used to study the sun
- Solar telescopeSolar telescopeA solar telescope is a special purpose telescope used to observe the Sun. Solar telescopes usually detect light with wavelengths in, or not far outside, the visible spectrum.-Professional solar telescopes:...
- Solar telescope
Planets
- PlanetPlanetA planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
s- Features
- Natural satelliteNatural satelliteA natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called its primary. The two terms are used synonymously for non-artificial satellites of planets, of dwarf planets, and of minor planets....
s (moons) - Planetary ringPlanetary ringA planetary ring is a ring of cosmic dust and other small particles orbiting around a planet in a flat disc-shaped region.The most notable planetary rings known in Earth's solar system are those around Saturn, but the other three gas giants of the solar system possess ring systems of their...
s
- Natural satellite
- Planets of the solar system
- MercuryMercury (planet)Mercury is the innermost and smallest planet in the Solar System, orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits...
- VenusVenusVenus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...
- EarthEarthEarth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
- MoonMoonThe Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...
- Moon
- MarsMarsMars is the fourth planet from the Sun in the Solar System. The planet is named after the Roman god of war, Mars. It is often described as the "Red Planet", as the iron oxide prevalent on its surface gives it a reddish appearance...
- Moons of Mars
- JupiterJupiterJupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
- Moons of Jupiter
- Rings of JupiterRings of JupiterThe planet Jupiter has a system of rings, known as the rings of Jupiter or the Jovian ring system. It was the third ring system to be discovered in the Solar System, after those of Saturn and Uranus. It was first observed in 1979 by the Voyager 1 space probe and thoroughly investigated in the 1990s...
- SaturnSaturnSaturn is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Saturn is named after the Roman god Saturn, equated to the Greek Cronus , the Babylonian Ninurta and the Hindu Shani. Saturn's astronomical symbol represents the Roman god's sickle.Saturn,...
- Moons of Saturn
- Rings of SaturnRings of SaturnThe rings of Saturn are the most extensive planetary ring system of any planet in the Solar System. They consist of countless small particles, ranging in size from micrometres to metres, that form clumps that in turn orbit about Saturn...
- UranusUranusUranus is the seventh planet from the Sun. It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. It is named after the ancient Greek deity of the sky Uranus , the father of Cronus and grandfather of Zeus...
- Moons of Uranus
- Rings of UranusRings of UranusThe planet Uranus has a system of rings intermediate in complexity between the more extensive set around Saturn and the simpler systems around Jupiter and Neptune. The rings of Uranus were discovered on March 10, 1977, by James L. Elliot, Edward W. Dunham, and Douglas J. Mink...
- NeptuneNeptuneNeptune is the eighth and farthest planet from the Sun in the Solar System. Named for the Roman god of the sea, it is the fourth-largest planet by diameter and the third largest by mass. Neptune is 17 times the mass of Earth and is slightly more massive than its near-twin Uranus, which is 15 times...
- Moons of Neptune
- Rings of NeptuneRings of NeptuneThe rings of Neptune consist primarily of five principal rings predicted in 1984 by André Brahic and imaged in 1989 by the Voyager 2 spacecraft...
- Features
- Dwarf planetDwarf planetA dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
s- Ceres
- PlutoPlutoPluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
- Moons of Pluto
- Haumea
- Moons of HaumeaMoons of HaumeaThe outer Solar System dwarf planet Haumea has two known moons, Hiiaka and Namaka, named after Hawaiian goddesses. These small moons were discovered in 2005, from observations of Haumea made at the large telescopes of the W. M. Keck Observatory in Hawaii....
- Moons of Haumea
- Makemake
- ErisEris (dwarf planet)Eris, formal designation 136199 Eris, is the most massive known dwarf planet in the Solar System and the ninth most massive body known to orbit the Sun directly...
- DysnomiaDysnomia (moon)- References :...
- Dysnomia
Small solar system bodies
Small Solar System bodySmall Solar System body
A small Solar System body is an object in the Solar System that is neither a planet nor a dwarf planet, nor a satellite of a planet or dwarf planet:...
- AsteroidAsteroidAsteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s- Minor planets
- :Category:Asteroid groups and families
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- Vulcanoid asteroidVulcanoid asteroidThe vulcanoids are a hypothetical population of asteroids that may orbit the Sun in a dynamically stable zone inside the orbit of the planet Mercury. They are named after the hypothetical planet Vulcan, whose existence was disproven in 1915...
s - Near-Earth asteroids
- Asteroid beltAsteroid beltThe asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...
- Trojan asteroidTrojan asteroidThe Jupiter Trojans, commonly called Trojans or Trojan asteroids, are a large group of objects that share the orbit of the planet Jupiter around the Sun. Relative to Jupiter, each Trojan librates around one of the planet's two Lagrangian points of stability, and , that respectively lie 60° ahead...
- CentaurCentaur (planetoid)Centaurs are an unstable orbital class of minor planets that behave with characteristics of both asteroids and comets. They are named after the mythological race of beings, centaurs, which were a mixture of horse and human...
- Neptune TrojanNeptune TrojanNeptune trojans are Kuiper belt object-like bodies in solar orbit that have the same orbital period as Neptune and follow roughly the same orbital path...
s - Minor planet moons
- Meteoroids
- 2 Pallas2 PallasPallas, formally designated 2 Pallas, is the second asteroid to have been discovered , and one of the largest. It is estimated to constitute 7% of the mass of the asteroid belt, and its diameter of 530–565 km is comparable to, or slightly larger than, that of 4 Vesta. It is however 20%...
- 3 Juno3 JunoJuno , formal designation 3 Juno in the Minor Planet Center catalogue system, was the third asteroid to be discovered and is one of the larger main-belt asteroids, being one of the two largest stony asteroids, along with 15 Eunomia. Juno is estimated to contain 1% of the total mass of the asteroid...
- 4 Vesta4 VestaVesta, formally designated 4 Vesta, is one of the largest asteroids, with a mean diameter of about . It was discovered by Heinrich Wilhelm Olbers on March 29, 1807, and is named after the Roman virgin goddess of home and hearth, Vesta....
- 10 Hygiea10 Hygiea10 Hygiea is an asteroid located in the asteroid belt. With somewhat oblong diameters of 350–500 km, and a mass estimated to be 2.9% of the total mass of the belt, it is the fourth largest asteroid by volume and mass...
- List of asteroids
- Meanings of asteroid namesMeanings of asteroid namesThis is a list of named minor planets , with links to the Wikipedia articles on the people, places, characters and concepts that they are named for.-See also:*List of minor planets*List of minor planets named after people...
- Pronunciation of asteroid namesPronunciation of asteroid namesThis page alphabetically lists the first thousand asteroids to be numbered, which are mostly in the main belt.See also Pronunciation of Trojan asteroids.-A:...
- Vulcanoid asteroid
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- Trans-Neptunian objectTrans-Neptunian objectA trans-Neptunian object is any minor planet in the Solar System that orbits the Sun at a greater distance on average than Neptune.The first trans-Neptunian object to be discovered was Pluto in 1930...
s- Kuiper beltKuiper beltThe Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...
- PlutinoPlutinoIn astronomy, a plutino is a trans-Neptunian object in 2:3 mean motion resonance with Neptune. For every 2 orbits that a plutino makes, Neptune orbits 3 times. Plutinos are named after Pluto, which follows an orbit trapped in the same resonance, with the Italian diminutive suffix -ino...
s- 90482 Orcus90482 Orcus90482 Orcus is a trans-Neptunian object in the Kuiper belt with a large moon. It was discovered on February 17, 2004 by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. Precovery images as early as November 8, 1951 were later identified...
- 28978 Ixion28978 Ixion28978 Ixion is a Kuiper belt object discovered on May 22, 2001. Ixion is a plutino and a very likely dwarf planet; its diameter of 650 km estimated by Spitzer makes it about the fifth largest plutino. It is named after Ixion, a figure from Greek mythology...
- 90482 Orcus
- CubewanoCubewanoA classical Kuiper belt object, also called a cubewano is a low-eccentricity Kuiper belt object that orbits beyond Neptune and is not controlled by an orbital resonance with Neptune. Cubewanos have orbits with semi-major axes in the 40–50 AU range and, unlike Pluto, do not cross Neptune’s orbit...
s - 20000 Varuna20000 Varuna20000 Varuna is a large classical Kuiper belt object and a probable dwarf planet. It previously had the provisional designation ' and has been precovered in plates dating back to 1953.-Name:Varuna is named after the Hindu deity,...
- 50000 Quaoar50000 Quaoar50000 Quaoar is a rocky trans-Neptunian object in the Kuiper belt with one known moon. Discovered on June 4, 2002 by astronomers Chad Trujillo and Michael Brown at the California Institute of Technology from images acquired at the Samuel Oschin Telescope at Palomar Observatory, it is thought by...
- 38628 Huya38628 Huya38628 Huya is a trans-Neptunian object . It was discovered in March 2000 by Ignacio Ferrin and announced on 24 October 2000. It is classified as a plutino being in a 2:3 mean motion resonance with Neptune. With a Spitzer size estimate of , this plutino is also a likely dwarf-planet. It is expected...
- Plutino
- Scattered discScattered discThe scattered disc is a distant region of the Solar System that is sparsely populated by icy minor planets, a subset of the broader family of trans-Neptunian objects. The scattered-disc objects have orbital eccentricities ranging as high as 0.8, inclinations as high as 40°, and perihelia greater...
- 90377 Sedna90377 Sedna90377 Sedna is a trans-Neptunian object discovered in 2003, which was about three times as far from the Sun as Neptune. For most of its orbit it is even further from the Sun, with its aphelion estimated at 960 astronomical units , making it one of the most distant known objects in the Solar System...
- CometCometA comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
s - List of periodic comets
- List of non-periodic comets
- Damocloids
- Hills cloud
- Oort cloudOort cloudThe Oort cloud , or the Öpik–Oort cloud , is a hypothesized spherical cloud of comets which may lie roughly 50,000 AU, or nearly a light-year, from the Sun. This places the cloud at nearly a quarter of the distance to Proxima Centauri, the nearest star to the Sun...
- Kuiper belt
Stars
- Stellar evolutionStellar evolutionStellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...
- Star formationStar formationStar formation is the process by which dense parts of molecular clouds collapse into a ball of plasma to form a star. As a branch of astronomy star formation includes the study of the interstellar medium and giant molecular clouds as precursors to the star formation process and the study of young...
- Pre–main sequence
- Main sequenceMain sequenceThe main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
- Horizontal branchHorizontal branchThe horizontal branch is a stage of stellar evolution which immediately follows the red giant branch in stars whose masses are similar to the Sun's...
- Asymptotic giant branchAsymptotic Giant BranchThe asymptotic giant branch is the region of the Hertzsprung-Russell diagram populated by evolving low to medium-mass stars. This is a period of stellar evolution undertaken by all low to intermediate mass stars late in their lives....
- Dredge-upDredge-upDredge-up refers to a period in the evolution of a star where a surface convection zone extends down to the layers where material has undergone nuclear fusion...
- Instability stripInstability stripThe Instability strip is a nearly vertical region in the Hertzsprung–Russell diagram which is occupied by pulsating variable stars .The instability strip intersects the main sequence in the region of A...
- Red clumpRed clumpThe red clump is a feature in the Hertzsprung-Russell diagram of stars. The red clump is considered the metal-rich counterpart to the horizontal branch. Stars in this part of the Hertzsprung-Russell diagram are sometimes called clump giants...
- PG 1159 starPG 1159 starA PG 1159 star, often also called a pre-degenerate, is a star with a hydrogen-deficient atmosphere which is in transition between being the central star of a planetary nebula and being a hot white dwarf...
- Mira variableMira variableMira variables , named after the star Mira, are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude in infrared and 2.5 magnitude in visual...
- Planetary nebulaPlanetary nebulaA planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life...
- Protoplanetary nebulaProtoplanetary nebulaA protoplanetary nebula or preplanetary nebula is an astronomical object which is at the short-lived episode during a star's rapid stellar evolution between the late asymptotic giant branch phase and the subsequent planetary nebula phase. A PPN emits strongly in infrared radiation, and is a...
- Luminous red novaLuminous red novaA luminous red nova is a stellar explosion thought to be caused by the merger of two stars. They are characterised by a distinct red colour, and a light curve that lingers with resurgent brightness in the infrared...
- Luminous blue variableLuminous blue variableLuminous blue variables, also known as S Doradus variables, are very bright, blue, hypergiant variable stars named after S Doradus, the brightest star of the Large Magellanic Cloud. They exhibit long, slow changes in brightness, punctuated by occasional outbursts in brightness during substantial...
- Wolf–Rayet star
- Supernova impostor
- SupernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
- HypernovaHypernovaHypernova , also known as a type 1c Supernova, refers to an incredibly large star that collapses at the end of its lifespan...
- Hertzsprung–Russell diagramHertzsprung–Russell diagramThe Hertzsprung–Russell diagram is a scatter graph of stars showing the relationship between the stars' absolute magnitudes or luminosities versus their spectral types or classifications and effective temperatures. Hertzsprung–Russell diagrams are not pictures or maps of the locations of the stars...
- Color–color diagram
- Star formation
- ProtostarProtostarA protostar is a large mass that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. The protostellar phase is an early stage in the process of star formation. For a one solar-mass star it lasts about 100,000 years...
s- Molecular cloudMolecular cloudA molecular cloud, sometimes called a stellar nursery if star formation is occurring within, is a type of interstellar cloud whose density and size permits the formation of molecules, most commonly molecular hydrogen ....
- H II regionH II regionAn H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived, blue stars forged in these regions emit copious amounts of ultraviolet light, ionizing the surrounding gas...
- H II region
- Bok globuleBok globuleBok globules are dark clouds of dense cosmic dust and gas in which star formation sometimes takes place. Bok globules are found within H II regions, and typically have a mass of about 2 to 50 solar masses contained within a region about a light year or so across...
- Young stellar objectYoung stellar objectYoung stellar object denotes a star in its early stage of evolution.This class consists of two groups of objects: protostars and pre–main sequence stars. Sometimes they are divided by mass - massive YSO , intermediate mass YSO and brown dwarfs....
- Herbig–Haro object
- Hayashi trackHayashi trackThe Hayashi track is a path taken by protostars in the Hertzsprung–Russell diagram after the protostellar cloud has reached approximate hydrostatic equilibrium...
- Hayashi limitHayashi limitHayashi limit is a constraint upon the maximum radius of a star for a given mass. When a star is fully within hydrostatic equilibrium—a condition where the inward force of gravity is matched by the outward pressure of the gas—then the star can not exceed the radius defined by the...
- Henyey track
- Orion variableOrion variableAn Orion variable is a variable star which exhibits irregular and eruptive variations in its luminosity and is typically associated with diffuse nebulae. It is thought that these are young stars which will later become regular, non-variable stars on the zero-age main sequence...
- T Tauri starT Tauri starT Tauri stars are a class of variable stars named after their prototype – T Tauri. They are found near molecular clouds and identified by their optical variability and strong chromospheric lines.-Characteristics:...
- FU Orionis star
- T Tauri star
- Herbig Ae/Be
- Molecular cloud
- Luminosity class
- Subdwarf starSubdwarf starA subdwarf star, sometimes denoted by "sd", is luminosity class VI under the Yerkes spectral classification system. They are defined as stars with luminosity 1.5 to 2 magnitudes lower than that of main-sequence stars of the same spectral type...
- Dwarf starDwarf starThe term dwarf star refers to a variety of distinct classes of stars.* Dwarf star alone generally refers to any main sequence star, a star of luminosity class V.** Red dwarfs are low-mass main sequence stars....
- Blue dwarf
- Red dwarfRed dwarfAccording to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....
- Subgiant
- Giant starGiant starA giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. Typically, giant stars have radii between 10 and 100 solar radii and luminosities between 10 and 1,000 times that of the Sun. Stars still more luminous than giants are...
- Blue giantBlue giantIn astronomy, a blue giant is a star with a spectral type of O or B and a luminosity class of III...
- Red giantRed giantA red giant is a luminous giant star of low or intermediate mass in a late phase of stellar evolution. The outer atmosphere is inflated and tenuous, making the radius immense and the surface temperature low, somewhere from 5,000 K and lower...
- Blue giant
- Bright giantBright giantThe luminosity class II in the Yerkes spectral classification is given to bright giants. These are stars which straddle the boundary between giants and supergiants, and the classification is in general given to giant stars with exceptionally high luminosity, but which are not sufficiently bright...
- SupergiantSupergiantSupergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
- Blue supergiantBlue supergiantBlue supergiants are supergiant stars of spectral type O or B.They are extremely hot and bright, with surface temperatures of 30,000-50,000 K. They typically have 10 to 50 solar masses on the Hertzsprung-Russell diagram, and can have radii up to about 25 solar radii...
- Red supergiantRed supergiantRed supergiants are supergiant stars of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive...
- Yellow supergiantYellow supergiantA yellow supergiant is a supergiant star of spectral type F or G. These stars usually have masses between 15 and 20 solar masses. These stars, like any other supergiant,...
- Blue supergiant
- HypergiantHypergiantA hypergiant is a star with a tremendous mass and luminosity, showing signs of a very high rate of mass loss.-Characteristics:...
- Yellow hypergiantYellow hypergiantGenerally speaking, a yellow hypergiant is a massive star with an extended atmosphere, which can be classified as spectral class from late A to K, with a mass of as much as 20-50 solar masses...
- Yellow hypergiant
- Blue stragglerBlue stragglerBlue stragglers are main sequence stars in open or globular clusters that are more luminous and bluer than stars at the main sequence turn-off point for the cluster. Blue stragglers were first discovered by Allan Sandage in 1953 while performing photometry of the stars in the globular cluster M3...
- Subdwarf star
- Stellar classificationStellar classificationIn astronomy, stellar classification is a classification of stars based on their spectral characteristics. The spectral class of a star is a designated class of a star describing the ionization of its chromosphere, what atomic excitations are most prominent in the light, giving an objective measure...
- O-type main-sequence star
- B-type main-sequence star
- A-type main-sequence star
- F-type main-sequence star
- G-type main-sequence star
- K-type main-sequence star
- M-type main-sequence star
- Be starBe starA Be star is a B-type star with prominent emission lines of hydrogen in its spectrum. The designation is combined by the spectral class, B, and the lowercase e denoting emission in the spectral classification system. Line emission from other atomic ions might be present as well, but is typically...
- OB starOB starOB stars are hot, massive stars of spectral types O or B which form in loosely organized groups called OB associations. They are short lived, and thus don't move very far from where they were formed within their life. During their lifetime, they will emit copious amounts of ultraviolet radiation...
- Subdwarf B starSubdwarf B starThe subdwarf B star is a kind of subdwarf star with spectral type B. They differ from the typical subdwarf star by being much hotter and brighter. They are from the "extreme horizontal branch stars" of the Hertzsprung–Russell diagram...
- Late-type starLate-type starIn stellar classification, a late-type star is a star of class K or class M. The term was coined in the early 20th century, when there was a belief that stars began their history as early-type stars of class O, B, or A, and subsequently cooled to late-type stars....
- Peculiar starPeculiar starIn astrophysics, peculiar stars have distinctly unusual metal abundances, at least in their surface layers.Chemically peculiar stars are common among hot main sequence stars...
- Am starAm starAn Am star or metallic-line star is a type of chemically peculiar star of spectral type A whose spectrum has strong and often variable absorption lines of metals such as zinc, strontium, zirconium, and barium, and deficiencies of others, such as calcium and scandium...
- Ap and Bp stars
- Rapidly oscillating Ap star
- Barium starBarium starBarium stars are G to K class giants, whose spectra indicate an overabundance of s-process elements by the presence of singly ionized barium, Ba II, at λ 455.4nm. Barium stars also show enhanced spectral features of carbon, the bands of the molecules CH, CN and C2...
- Carbon starCarbon starA carbon star is a late-type star similar to a red giant whose atmosphere contains more carbon than oxygen; the two elements combine in the upper layers of the star, forming carbon monoxide, which consumes all the oxygen in the atmosphere, leaving carbon atoms free to form other carbon compounds,...
- CH star
- Extreme helium starExtreme helium starAn extreme helium star is a low-mass supergiant that is almost devoid of hydrogen, the most common chemical element of the Universe...
- Lambda Boötis starLambda Boötis starA Lambda Boötis star is a type of peculiar star which has an unusually low abundance of iron peak elements in its surface layers. One possible explanation for this is that it is the result of accretion of metal-poor gas from a circumstellar disc. The prototype is Lambda Boötis....
- Lead starLead starA lead star is a low-metallicity star with an overabundance of lead and bismuth as compared to other products of the S-process....
- Mercury-manganese starMercury-manganese starA mercury-manganese star is a type of chemically peculiar star with a prominent spectral line at 398.4 nm, due to absorption from ionized mercury...
- S-type starS-type starA star with spectral type S is a late-type giant star whose spectrum displays bands from zirconium oxide in addition to titanium oxide which is characteristically exhibited by K and M class giant stars...
- Shell starShell starA shell star, also termed Gamma Cassiopeiae variable , is a star having a spectrum that exhibits features indicating a circumstellar disc of gas surrounding the star at the equator. They exhibit irregular variations in their luminosity due to the outflow of matter...
- Technetium starTechnetium starA technetium star, or more properly a Tc-rich star, is a star whose stellar spectrum contains absorption lines of the light radioactive metal technetium. The most stable isotope of technetium is 98Tc with a half-life of 4.2 million years, which is too short a time to allow the metal to be material...
- Am star
- Remnants
- White dwarfWhite dwarfA white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
- Black dwarfBlack dwarfA black dwarf is a hypothetical stellar remnant, created when a white dwarf becomes sufficiently cool to no longer emit significant heat or light...
- Helium planetHelium planetA helium planet is a theoretical type of planet that may form via mass loss from a low mass white dwarf star. Ordinary gas giant planets such as Jupiter and Saturn consist primarily of hydrogen, with helium as a secondary component...
- Black dwarf
- Neutron starNeutron starA neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
- PulsarPulsarA pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
- MagnetarMagnetarA magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious high-energy electromagnetic radiation, particularly X-rays and gamma rays...
- Pulsar
- Stellar black holeStellar black holeA stellar black hole is a black hole formed by the gravitational collapse of a massive star. They have masses ranging from about 3 to several tens of solar masses...
- Compact starCompact starIn astronomy, the term compact star is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes. These objects are all small for their mass...
- Quark starQuark starA quark star or strange star is a hypothetical type of exotic star composed of quark matter, or strange matter. These are ultra-dense phases of degenerate matter theorized to form inside particularly massive neutron stars....
- Exotic starExotic starAn exotic star is a compact star composed of something other than electrons, protons, and neutrons balanced against gravitational collapse by degeneracy pressure or other quantum properties...
- Quark star
- Stellar core: EF EridaniEF EridaniEF Eridani is a variable star of the type known as polars, AM Herculis stars, or magnetic cataclysmic variable stars. Historically it has varied between apparent magnitudes 14.5 and 17.3, although since 1995 it has generally remained at the lower limit...
- White dwarf
- Failed and theoretical stars
- Substellar objectSubstellar objectA substellar object, sometimes called a lump, is an astronomical object whose mass is smaller than the smallest mass, approximately 0.08 solar masses, at which a star can sustain hydrogen fusion...
- Brown dwarfBrown dwarfBrown dwarfs are sub-stellar objects which are too low in mass to sustain hydrogen-1 fusion reactions in their cores, which is characteristic of stars on the main sequence. Brown dwarfs have fully convective surfaces and interiors, with no chemical differentiation by depth...
- Sub-brown dwarfSub-brown dwarfA sub-brown dwarf is an astronomical object of planetary mass that is not orbiting a star and is not considered to be a brown dwarf because its mass is below the limiting mass for thermonuclear fusion of deuterium ....
- Sub-brown dwarf
- PlanetarPlanetar (astronomy)Planetar is a term used in astronomy that refers to one of two things:* Brown dwarfs — objects intermediate in size between planets and stars — but having formed similarly to planets....
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- Brown dwarf
- Boson star
- Dark starDark star (dark matter)A dark star is a theoretical type of star that may have existed early in the history of the universe before conventional stars were able to form. They would be composed mostly of normal matter, like modern stars, but a high concentration of neutralino dark matter within them would generate heat via...
- QuasistarQuasistarA quasi-star is a hypothetical type of extremely massive star that may have existed very early in the history of the Universe...
- Thorne–Żytkow object
- Iron starIron starIn astronomy, an iron star is a hypothetical type of star that could occur in the universe in 101500 years. The premise behind iron stars states that cold fusion occurring via quantum tunnelling would cause the light nuclei in ordinary matter to fuse into iron-56 nuclei...
- Substellar object
- Stellar nucleosynthesisStellar nucleosynthesisStellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the elements heavier than hydrogen. Some small quantity of these reactions also occur on the stellar surface under various circumstances...
- Alpha process
- Triple-alpha processTriple-alpha processThe triple alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei are transformed into carbon.Older stars start to accumulate helium produced by the proton–proton chain reaction and the carbon–nitrogen–oxygen cycle in their cores...
- Proton–proton chain reaction
- Helium flashHelium flashA helium flash is the runaway fusion of helium in the core of low mass stars of less than about 2.25 solar masses and greater than about 0.5 solar mass, or on the surface of an accreting white dwarf star. They may also occur in the outer layers of larger stars in shell flashes...
- CNO cycleCNO cycleThe CNO cycle is one of two sets of fusion reactions by which stars convert hydrogen to helium, the other being the proton–proton chain. Unlike the proton–proton chain reaction, the CNO cycle is a catalytic cycle. Theoretical models show that the CNO cycle is the dominant source of energy in stars...
- Lithium burningLithium burningLithium is generally present in brown dwarfs and not in low-mass stars. Stars, which achieve the high temperature necessary for fusing hydrogen, rapidly deplete their lithium. This occurs by a collision of lithium-7 and a proton producing two helium-4 nuclei. The temperature necessary for this...
- Carbon-burning process
- Neon-burning process
- Oxygen-burning process
- Silicon-burning process
- S-processS-processThe S-process or slow-neutron-capture-process is a nucleosynthesis process that occurs at relatively low neutron density and intermediate temperature conditions in stars. Under these conditions the rate of neutron capture by atomic nuclei is slow relative to the rate of radioactive beta-minus decay...
- R-processR-processThe r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56,...
- FusorFusor (astronomy)A fusor is a term proposed to the IAU by Gibor Basri, Professor of Astronomy at the University of California, Berkeley, to help clarify the nomenclature of celestial bodies...
- NovaNovaA nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner...
- Nova remnantNova remnantA nova remnant is made up of the material either left behind by the gigantic explosion of a star in a nova, or from the bubbles of gas blasted away in a recurrent nova. It has an expansion velocity of around 1000 km/s, and has a lifetime of a few centuries. Considering their short lifetimes, nova...
- Nova remnant
- Stellar structureStellar structureStars of different mass and age have varying internal structures. Stellar structure models describe the internal structure of a star in detail and make detailed predictions about the luminosity, the color and the future evolution of the star....
- Solar coreSolar coreThe core of the Sun is considered to extend from the center to about 0.2 to 0.25 solar radius. It is the hottest part of the Sun and of the Solar System. It has a density of up to 150 g/cm³ and a temperature of close to 15,000,000 kelvin...
- Convection zoneConvection zoneThe convection zone of a star is the range of radii in which energy is transported primarily by convection. In the radiation zone, energy is transported by radiation...
- MicroturbulenceMicroturbulenceMicroturbulence is a form of turbulence that varies over small distance scales. -Stellar:Microturbulence is one of several mechanisms that can cause broadening of the absorption lines in the stellar spectrum...
- Solar-like oscillationsSolar-like oscillationsThe term solar-like oscillations refers to oscillations in other stars that are excited in the same way as those in the Sun, namely by convection in its outer layers.-See also:* asteroseismology* helioseismology* variable stars* Procyon...
- Microturbulence
- Radiation zoneRadiation zoneThe radiation zone is the middle zone in the Sun's interior. Energy travels out of the core into the radiation zone. Energy that travels through the radiation zone is in the form of electromagnetic radiation. The radiation zone is so dense that the waves bounce around...
- PhotospherePhotosphereThe photosphere of an astronomical object is the region from which externally received light originates. The term itself is derived from Ancient Greek roots, φῶς, φωτός/phos, photos meaning "light" and σφαῖρα/sphaira meaning "sphere", in reference to the fact that it is a spheric surface perceived...
- StarspotStarspotStarspots are equivalent to sunspots but located on other stars. Spots the size of sunspots are very hard to detect since they are too small to cause fluctuations in brightness...
- ChromosphereChromosphereThe chromosphere is a thin layer of the Sun's atmosphere just above the photosphere, roughly 2,000 kilometers deep....
- CoronaCoronaA corona is a type of plasma "atmosphere" of the Sun or other celestial body, extending millions of kilometers into space, most easily seen during a total solar eclipse, but also observable in a coronagraph...
- Stellar windStellar windA stellar wind is a flow of neutral or charged gas ejected from the upper atmosphere of a star. It is distinguished from the bipolar outflows characteristic of young stars by being less collimated, although stellar winds are not generally spherically symmetric.Different types of stars have...
- Stellar-wind bubble
- AsteroseismologyAsteroseismologyAsteroseismology also known as stellar seismology is the science that studies the internal structure of pulsating stars by the interpretation of their frequency spectra. Different oscillation modes penetrate to different depths inside the star...
- Eddington luminosityEddington luminosityThe Eddington luminosity in a star is defined as the point where the gravitational force inwards equals the continuum radiation force outwards, assuming hydrostatic equilibrium and spherical symmetry. When exceeding the Eddington luminosity, a star would initiate a very intense continuum-driven...
- Kelvin–Helmholtz mechanism
- Solar core
- Properties
- Star designationStar designationDesignations of stars are done by the International Astronomical Union . Many of the star names in use today were inherited from the time before the IAU existed. Other names, mainly for variable stars , are being added all the time.Approximately 10,000 stars are visible to the naked eye...
- Stellar dynamicsStellar dynamicsStellar dynamics is the branch of astrophysics which describes in a statistical way the collective motions of stars subject to their mutual gravity. The long range of gravity and the slow "relaxation" of stellar systems prevent the use of the methods of statistical physics...
- Effective temperatureEffective temperatureThe effective temperature of a body such as a star or planet is the temperature of a black body that would emit the same total amount of electromagnetic radiation...
- Stellar kinematicsStellar kinematicsStellar kinematics is the study of the movement of stars without needing to understand how they acquired their motion. This differs from stellar dynamics, which takes into account gravitational effects...
- Stellar magnetic fieldStellar magnetic fieldA stellar magnetic field is a magnetic field generated by the motion of conductive plasma inside a star. This motion is created through convection, which is a form of energy transport involving the physical movement of material. A localized magnetic field exerts a force on the plasma, effectively...
- MagnitudeMagnitude (astronomy)Magnitude is the logarithmic measure of the brightness of an object, in astronomy, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.-Background:...
- Absolute magnitudeAbsolute magnitudeAbsolute magnitude is the measure of a celestial object's intrinsic brightness. it is also the apparent magnitude a star would have if it were 32.6 light years away from Earth...
- Absolute magnitude
- Solar massSolar massThe solar mass , , is a standard unit of mass in astronomy, used to indicate the masses of other stars and galaxies...
- MetallicityMetallicityIn astronomy and physical cosmology, the metallicity of an object is the proportion of its matter made up of chemical elements other than hydrogen and helium...
- Stellar rotationStellar rotationStellar rotation is the angular motion of a star about its axis. The rate of rotation can be measured from the spectrum of the star, or by timing the movements of active features on the surface....
- UBV photometric systemUBV photometric systemUBV photometric system, also called the Johnson system , is a wide band photometric system for classifying stars according to their colors. It is the first known standardized photoelectric photometric system. The letters U, B, and V stand for ultraviolet, blue, and visual magnitudes, which are...
- Variable starVariable starA star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
- Star designation
- Star systemStar systemA star system or stellar system is a small number of stars which orbit each other, bound by gravitational attraction. A large number of stars bound by gravitation is generally called a star cluster or galaxy, although, broadly speaking, they are also star systems.-Binary star systems:A stellar...
s- Binary starBinary starA binary star is a star system consisting of two stars orbiting around their common center of mass. The brighter star is called the primary and the other is its companion star, comes, or secondary...
- Contact binaryContact binaryIn astronomy, a contact binary is a binary star system whose component stars are so close that they touch each other or have merged to share their gaseous envelopes. A binary system whose stars share an envelope may also be called an overcontact binary...
- Common envelopeCommon envelopeIn astronomy, a common envelope refers to a short-lived phase in the evolution of a binary star in which the largest of the two stars has initiated unstable mass transfer to its companion star. Mass transfer is unstable when the radius of the donor star expands more rapidly or shrinks less...
- Contact binary
- Multiple starMultiple starA multiple star consists of three or more stars which appear from the Earth to be close to one another in the sky. This may result from the stars being physically close and gravitationally bound to each other, in which case it is physical, or this closeness may be merely apparent, in which case...
- Accretion discAccretion discAn accretion disc is a structure formed by diffuse material in orbital motion around a central body. The central body is typically a star. Gravity causes material in the disc to spiral inward towards the central body. Gravitational forces compress the material causing the emission of...
- Planetary systemPlanetary systemA planetary system consists of the various non-stellar objects orbiting a star such as planets, dwarf planets , asteroids, meteoroids, comets, and cosmic dust...
- Earth's Solar SystemSolar SystemThe Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
- Binary star
- Earth-centric obvservation of stars
- Pole starPole starThe term "Pole Star" usually refers to Polaris, which is the current northern pole star, also known as the North Star.In general, however, a pole star is a visible star, especially a prominent one, that is approximately aligned with the Earth's axis of rotation; that is, a star whose apparent...
- Circumpolar starCircumpolar starA circumpolar star is a star that, as viewed from a given latitude on Earth, never sets , due to its proximity to one of the celestial poles...
- MagnitudeMagnitude (astronomy)Magnitude is the logarithmic measure of the brightness of an object, in astronomy, measured in a specific wavelength or passband, usually in optical or near-infrared wavelengths.-Background:...
- Apparent magnitudeApparent magnitudeThe apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
- Photographic magnitudePhotographic magnitudeBefore the advent of photometers which accurately measure the brightness of astronomical objects, the apparent magnitude of an object was obtained by taking a picture of it with a camera. These images, made on photoemulsive film or plates, were more sensitive to the blue end of the visual spectrum...
- color-color diagramColor-color diagramIn astronomy, color–color diagrams are a means of comparing the apparent magnitudes of stars at different wavelengths. Astronomers typically observe at narrow bands around certain wavelengths, and objects observed will have different brightnesses in each band. The difference the brightness in two...
- Apparent magnitude
- Radial velocityRadial velocityRadial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...
- Proper motionProper motionThe proper motion of a star is its angular change in position over time as seen from the center of mass of the solar system. It is measured in seconds of arc per year, arcsec/yr, where 3600 arcseconds equal one degree. This contrasts with radial velocity, which is the time rate of change in...
- Parallax#Stellar parallax
- Photometric-standard star
- Pole star
- Lists of stars
- List of proper names of stars
- List of Arabic star names
- Traditional Chinese star namesTraditional Chinese star namesTraditional Chinese star names are the names of stars used in ancient Chinese literature, history, religion, mythology, folklore, Chinese opera and such methods of divination as astrology, horoscope and Feng shui...
- List of most massive stars
- List of least massive stars
- List of largest known stars
- List of brightest stars
- Historical brightest starsHistorical brightest starsThe Solar System and all of the visible stars are in different orbits about the core of the Milky Way galaxy. Thus, their relative positions change over time, and for the nearer stars this movement can be measured. As a star moves toward or away from us, its apparent brightness changes. Sirius...
- Historical brightest stars
- List of most luminous stars
- List of nearest stars
- List of exoplanetary host stars
- List of brown dwarfs
- List of planetary nebulae
- List of novae
- List of supernovae
- List of supernova remnants
- List of supernova candidates
- Timeline of stellar astronomyTimeline of stellar astronomyTimeline of stellar astronomy* 134 BC — Hipparchus creates the magnitude scale of stellar apparent luminosities* 185 AD — Chinese astronomers become the first to observe a supernova, the SN 185...
Variable stars
Variable starVariable star
A star is classified as variable if its apparent magnitude as seen from Earth changes over time, whether the changes are due to variations in the star's actual luminosity, or to variations in the amount of the star's light that is blocked from reaching Earth...
- Pulsating
- Cepheids and cepheid-like
- Cepheid variableCepheid variableA Cepheid is a member of a class of very luminous variable stars. The strong direct relationship between a Cepheid variable's luminosity and pulsation period, secures for Cepheids their status as important standard candles for establishing the Galactic and extragalactic distance scales.Cepheid...
- Type II Cepheids
- RR Lyrae variableRR Lyrae variableRR Lyrae variables are periodic variable stars, commonly found in globular clusters, and often used as standard candles to measure galactic distances.This type of variable is named after the prototype, the variable star RR Lyrae in the constellation Lyra....
- Delta Scuti variableDelta Scuti variableA Delta Scuti variable is a variable star which exhibits variations in its luminosity due to both radial and non-radial pulsations of the star's surface. Typical brightness fluctuations are from 0.003 to 0.9 magnitudes in V over a period of a few hours, although the amplitude and period of the...
- SX Phoenicis variableSX Phoenicis variableAn SX Phoenicis variable is a type of variable star. These stars exhibit a short period pulsation behavior that varies on time scales of 0.03–0.08 days . They have spectral classifications in the range A2-F5 and vary in magnitude by up to 0.7...
- Cepheid variable
- Blue-white with early spectra
- Beta Cephei variableBeta Cephei variableBeta Cephei variables are variable stars which exhibit variations in their brightness due to pulsations of the stars' surfaces. The point of maximum brightness roughly corresponds to the maximum contraction of the star. Typically, Beta Cephei variables change in brightness by 0.01 to 0.3...
- PV Telescopii variablePV Telescopii variablePV Telescopii variable is a type of variable star that is established in the General Catalogue of Variable Stars with the acronym PVTEL. This class of variables are defined as "helium supergiant Bp stars with weak hydrogen lines and enhanced lines of He and C"...
- Beta Cephei variable
- Long Period and SemiregularLong period variableA long period variable is a type of variable star in which variations in brightness occur over long timescales of months or years. Long period variables are giant stars and brighter, from spectral class F and redwards, but most are red giants and AGB giants, meaning spectral class M, S or C...
- = Mira variableMira variableMira variables , named after the star Mira, are a class of pulsating variable stars characterized by very red colors, pulsation periods longer than 100 days, and light amplitudes greater than one magnitude in infrared and 2.5 magnitude in visual...
- Semiregular variable
- Slow irregular variableSlow irregular variableA slow irregular variable is a variable star that exhibit no or very poorly defined periodicity in their slowly changing light emissions. Most of them are late spectral types K and M, S stars or carbon stars...
- = Mira variable
- Other
- RV Tauri variableRV Tauri variableRV Tauri variables are supergiant variable stars. They exhibit changes in luminosity which are tied to radial pulsations of their surfaces. Their changes in brightness are also correlated with changes in their spectral type. While at their brightest, the stars have spectral types F or G. At...
- Alpha Cygni variableAlpha Cygni variableAlpha Cygni variables are variable stars which exhibit non-radial pulsations, meaning that some portions of the stellar surface are contracting at the same time others parts expand. They are supergiant stars of spectral types B or A...
- Pulsating white dwarfPulsating white dwarfA pulsating white dwarf is a white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. Known types of pulsating white dwarfs include DAV, or ZZ Ceti, stars, with hydrogen-dominated atmospheres and the spectral type DA, pp. 891, 895; DBV, or V777 Her,...
- RV Tauri variable
- Cepheids and cepheid-like
- Eruptive
- Pre-main sequence starPre-main sequence starA pre-main-sequence star is a star in the stage when it has not yet reached the main sequence...
- Herbig Ae/Be
- Orion variableOrion variableAn Orion variable is a variable star which exhibits irregular and eruptive variations in its luminosity and is typically associated with diffuse nebulae. It is thought that these are young stars which will later become regular, non-variable stars on the zero-age main sequence...
- FU Orionis star
- Main SequenceMain sequenceThe main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell...
- Wolf-Rayet starWolf-Rayet starWolf–Rayet stars are evolved, massive stars , which are losing mass rapidly by means of a very strong stellar wind, with speeds up to 2000 km/s...
- Flare starFlare starA flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to magnetic reconnection in the atmospheres of the stars. The brightness increase is...
- Wolf-Rayet star
- Giants and supergiants
- Luminous blue variableLuminous blue variableLuminous blue variables, also known as S Doradus variables, are very bright, blue, hypergiant variable stars named after S Doradus, the brightest star of the Large Magellanic Cloud. They exhibit long, slow changes in brightness, punctuated by occasional outbursts in brightness during substantial...
- Gamma Cassiopeiae variable
- R Coronae Borealis variableR Coronae Borealis variableA R Coronae Borealis variable is an eruptive variable star that varies in luminosity in two modes, one low amplitude pulsation , and one irregular unpredictably sudden fading by 1 to 9 magnitudes...
- Luminous blue variable
- Eruptive binary
- RS Canum Venaticorum variableRS Canum Venaticorum variableRS Canum Venaticorum variables are a type of variable star. They are close binary stars having active chromospheres which can cause large stellar spots. These spots are believed to cause variations in their observed luminosity...
- RS Canum Venaticorum variable
- Cataclysmic or explosive
- Cataclysmic variable starCataclysmic variable starCataclysmic variable stars are stars which irregularly increase in brightness by a large factor, then drop back down to a quiescent state...
- Dwarf novaDwarf novaA U Geminorum-type variable star, or dwarf nova is a type of cataclysmic variable starhttp://www.sai.msu.su/groups/cluster/gcvs/gcvs/iii/vartype.txt consisting of a close binary star system in which one of the components is a white dwarf, which accretes matter from its companion...
- NovaNovaA nova is a cataclysmic nuclear explosion in a star caused by the accretion of hydrogen on to the surface of a white dwarf star, which ignites and starts nuclear fusion in a runaway manner...
- SupernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
- Z Andromedae
- Cataclysmic variable star
- Pre-main sequence star
- Rotating
- Non-spherical
- Ellipsoidal
- Stellar spots
- FK Comae Berenices
- BY Draconis variableBY Draconis variableBY Draconis variables are main sequence variable stars of late spectral types, usually K or M. The name comes from the archetype for this category of variable star system, BY Draconis. They exhibit variations in their luminosity due to rotation of the star coupled with star spots, and other...
- Magnetic fields
- Alpha² Canum Venaticorum variable
- SX Arietis
- PulsarPulsarA pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
- Non-spherical
- Eclipsing binary
- Algol variableAlgol variableAlgol variables or Algol-type binaries are a class of eclipsing binary stars where the orbital plane of the stars are coincident with the line of sight from Earth. When the cooler component passes in front of the hotter one, part of the latter's light is blocked, and the total brightness of the...
- Beta Lyrae variableBeta Lyrae variableBeta Lyrae variables are a class of close binary stars. Their total brightness is variable because the two component stars orbit each other, and in this orbit one component periodically passes in front of the other one, thereby blocking its light. The two component stars of Beta Lyrae systems are...
- W Ursae Majoris variableW Ursae Majoris variableA W Ursae Majoris variable is a type of eclipsing binary variable star. These stars are close binaries, whose surfaces are in contact with one another. They are termed contact binaries because the two stars touch and they essentially share material in their outer layers. Through the neck between...
- Algol variable
Supernavae
SupernovaSupernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
- Classes
- Type Ia supernovaType Ia supernovaA Type Ia supernova is a sub-category of supernovae, which in turn are a sub-category of cataclysmic variable stars, that results from the violent explosion of a white dwarf star. A white dwarf is the remnant of a star that has completed its normal life cycle and has ceased nuclear fusion...
- Type Ib and Ic supernovaeType Ib and Ic supernovaeTypes Ib and Ic supernovae are categories of stellar explosions that are caused by the core collapse of massive stars. These stars have shed their outer envelope of hydrogen, and, when compared to the spectrum of Type Ia supernovae, they lack the absorption line of silicon...
- Type II (IIP and IIL)Type II supernovaA Type II supernova results from the rapid collapse and violent explosion of a massive star. A star must have at least 9 times, and no more than 40–50 times the mass of the Sun for this type of explosion. It is distinguished from other types of supernova by the presence of hydrogen in its spectrum...
- Type Ia supernova
- Related
- Near-Earth supernovaNear-Earth supernovaA near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth to have noticeable effects on its biosphere.-Effects on the planet:...
- Supernova impostor
- HypernovaHypernovaHypernova , also known as a type 1c Supernova, refers to an incredibly large star that collapses at the end of its lifespan...
- Quark-novaQuark-novaA quark-nova is a hypothetical type of supernova that could occur if a neutron star spontaneously collapsed to become a quark star. The concept of quark-novae was suggested by Dr. Rachid Ouyed and Drs. Dey and Dey...
- Pulsar kicksPulsar kicks|- style="vertical-align: top;"| Distance | 7.700 LyA pulsar kick refers to the observed phenomenon that the neutron star remnants of many supernovae do not move with the velocity of their progenitor star, but rather with a substantially greater speed...
- Near-Earth supernova
- Structure
- Pair-instability supernovaPair-instability supernovaA pair-instability supernova occurs when pair production, the production of free electrons and positrons in the collision between atomic nuclei and energetic gamma rays, reduces thermal pressure inside a supermassive star's core...
- Supernova nucleosynthesisSupernova nucleosynthesisSupernova nucleosynthesis is the production of new chemical elements inside supernovae. It occurs primarily due to explosive nucleosynthesis during explosive oxygen burning and silicon burning...
- P-processP-processThe term p-process is used in two ways in the scientific literature concerning the astrophysical origin of the elements . Originally it referred to a proton capture process which is the source of certain, naturally occurring, proton-rich isotopes of the elements from selenium to mercury...
- R-processR-processThe r-process is a nucleosynthesis process, likely occurring in core-collapse supernovae responsible for the creation of approximately half of the neutron-rich atomic nuclei that are heavier than iron. The process entails a succession of rapid neutron captures on seed nuclei, typically Ni-56,...
- Gamma-ray burst
- Carbon detonationCarbon detonationCarbon detonation is the violent re-ignition of thermonuclear fusion in a dead star, which produces a Type Ia supernova. A white dwarf undergoes carbon detonation only if it has a normal binary companion which is close enough to the dwarf star to dump sufficient amounts of matter onto the dwarf,...
- Pair-instability supernova
- Progenitors
- Luminous blue variableLuminous blue variableLuminous blue variables, also known as S Doradus variables, are very bright, blue, hypergiant variable stars named after S Doradus, the brightest star of the Large Magellanic Cloud. They exhibit long, slow changes in brightness, punctuated by occasional outbursts in brightness during substantial...
- Wolf–Rayet star
- SupergiantSupergiantSupergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
- Blue supergiantBlue supergiantBlue supergiants are supergiant stars of spectral type O or B.They are extremely hot and bright, with surface temperatures of 30,000-50,000 K. They typically have 10 to 50 solar masses on the Hertzsprung-Russell diagram, and can have radii up to about 25 solar radii...
- Red supergiantRed supergiantRed supergiants are supergiant stars of spectral type K or M. They are the largest stars in the universe in terms of volume, although they are not the most massive...
- Yellow supergiantYellow supergiantA yellow supergiant is a supergiant star of spectral type F or G. These stars usually have masses between 15 and 20 solar masses. These stars, like any other supergiant,...
- Blue supergiant
- HypergiantHypergiantA hypergiant is a star with a tremendous mass and luminosity, showing signs of a very high rate of mass loss.-Characteristics:...
- Yellow hypergiantYellow hypergiantGenerally speaking, a yellow hypergiant is a massive star with an extended atmosphere, which can be classified as spectral class from late A to K, with a mass of as much as 20-50 solar masses...
- Yellow hypergiant
- White dwarfWhite dwarfA white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
- Luminous blue variable
- Remnants
- Supernova remnantSupernova remnantA supernova remnant is the structure resulting from the explosion of a star in a supernova. The supernova remnant is bounded by an expanding shock wave, and consists of ejected material expanding from the explosion, and the interstellar material it sweeps up and shocks along the way.There are two...
- Neutron starNeutron starA neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
- PulsarPulsarA pulsar is a highly magnetized, rotating neutron star that emits a beam of electromagnetic radiation. The radiation can only be observed when the beam of emission is pointing towards the Earth. This is called the lighthouse effect and gives rise to the pulsed nature that gives pulsars their name...
- MagnetarMagnetarA magnetar is a type of neutron star with an extremely powerful magnetic field, the decay of which powers the emission of copious high-energy electromagnetic radiation, particularly X-rays and gamma rays...
- Stellar black holeStellar black holeA stellar black hole is a black hole formed by the gravitational collapse of a massive star. They have masses ranging from about 3 to several tens of solar masses...
- Pulsar
- Compact starCompact starIn astronomy, the term compact star is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes. These objects are all small for their mass...
- SupergiantSupergiantSupergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
- Quark starQuark starA quark star or strange star is a hypothetical type of exotic star composed of quark matter, or strange matter. These are ultra-dense phases of degenerate matter theorized to form inside particularly massive neutron stars....
- Exotic starExotic starAn exotic star is a compact star composed of something other than electrons, protons, and neutrons balanced against gravitational collapse by degeneracy pressure or other quantum properties...
- Quark star
- Supernova remnant
- iscovery
- Guest starGuest star (astronomy)In Chinese astronomy, the term guest star refers to a star which has suddenly appeared visible in the place where no star had previously been observed and becomes invisible again after some time. The term is a literal translation from ancient Chinese astronomical records...
- History of supernova observationHistory of supernova observationThe known history of supernova observation goes back to 185 CE, when supernova SN 185 appeared, the oldest appearance of a supernova recorded by humankind...
- Timeline of white dwarfs, neutron stars, and supernovaeTimeline of white dwarfs, neutron stars, and supernovaeTimeline of white dwarfs, neutron stars, and supernovaeNote that this list is mainly about the development of knowledge, but also about some supernovae taking place. For a separate list of the latter, see the article List of supernovae...
- Guest star
- Notable
- List of supernovae
- List of supernova remnants
- List of supernova candidates
- List of most massive stars
- Supernovae in fictionSupernovae in fictionIn works of fiction, supernovae are often used as plot devices.*In the 1999 RTS game Homeworld, one of the missions take place in a dust belt near an active supernova. The protagonists' target is a nearby research station observing the event...
- SN 1054SN 1054SN 1054 is a supernova that was first observed as a new "star" in the sky on July 4, 1054 AD, hence its name, and that lasted for a period of around two years. The event was recorded in multiple Chinese and Japanese documents and in one document from the Arab world...
- SupergiantSupergiantSupergiants are among the most massive stars. They occupy the top region of the Hertzsprung-Russell diagram. In the Yerkes spectral classification, supergiants are class Ia or Ib . They typically have bolometric absolute magnitudes between -5 and -12...
- Crab NebulaCrab NebulaThe Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus...
- Crab Nebula
- Tycho'sSN 1572SN 1572 , "B Cassiopeiae" , or 3C 10 was a supernova of Type Ia in the constellation Cassiopeia, one of about eight supernovae visible to the naked eye in historical records...
- Kepler'sSN 1604Supernova 1604, also known as Kepler's Supernova, Kepler's Nova or Kepler's Star, was a supernova that occurred in the Milky Way, in the constellation Ophiuchus. , it is the last supernova to have been unquestionably observed in our own galaxy, occurring no farther than 6 kiloparsecs or about...
- SN 1987ASN 1987ASN 1987A was a supernova in the outskirts of the Tarantula Nebula in the Large Magellanic Cloud, a nearby dwarf galaxy. It occurred approximately 51.4 kiloparsecs from Earth, approximately 168,000 light-years, close enough that it was visible to the naked eye. It could be seen from the Southern...
- SN 185SN 185SN 185 was a supernova which appeared in the year 185 AD, near the direction of Alpha Centauri, between the constellations Circinus and Centaurus, centered at RA Dec , in Circinus. This "guest star" was observed by Chinese astronomers in the Book of Later Han, and may have been recorded in Roman...
- SN 1006SN 1006SN 1006 was a supernova, widely seen on Earth beginning in the year 1006 AD; Earth was about 7,200 light-years away from the supernova. It was the brightest apparent magnitude stellar event in recorded history reaching an estimated -7.5 visual magnitude...
- SN 2003fg
- Vela Supernova RemnantVela Supernova RemnantThe Vela supernova remnant is a supernova remnant in the southern constellation Vela. Its source supernova exploded approximately 11,000-12,300 years ago...
- Remnant G1.9+0.3Supernova remnant G1.9+0.3Supernova remnant G1.9+0.3 is the youngest known supernova remnant in the Milky Way Galaxy. The remnant's young age was established by combining data from NASA's Chandra X-ray Observatory and the VLA radio observatory, and is believed to have exploded about 25,000 years ago, and the signal began...
- SN 2007biSN 2007biSN 2007bi was an extremely energetic supernova discovered early in 2007 by the international Nearby Supernova Factory based at the U.S. Department of Energy's Lawrence Berkeley National Laboratory. The precursor star is estimated to have had 200 solar masses at the time of its formation and around...
- Research
- Supernova Cosmology ProjectSupernova Cosmology ProjectThe Supernova Cosmology Project is one of two research teams that determined the likelihood of an accelerating universe and therefore a positive Cosmological constant, using data from the redshift of Type Ia supernovae...
- High-z Supernova Search TeamHigh-z Supernova Search TeamThe High-z Supernova Search Team was an international cosmology collaboration which used Type Ia Supernovae to chart the expansion of the Universe. The team was formed in 1994 by Brian P. Schmidt, then a post-doctoral research associate at Harvard University, and Nicholas B. Suntzeff, a staff...
- Texas Supernova SearchTexas Supernova SearchTexas Supernova Search is one of many ongoing projects to identify and record supernova events. The project is led by Robert Quimby and to date has found 35 supernovae, 29 of which they were the first to report on...
- Nearby Supernova FactoryNearby Supernova FactoryThe Nearby Supernova Factory is a collaborative experiment led by Greg Aldering, designed to collect data on more Type Ia supernovae than have ever been studied in a single project before, and by studying them, to increase understanding of the expanding universe and "Dark Energy."The project began...
- Supernova Legacy SurveySupernova Legacy SurveyThe Supernova Legacy Survey Program is a project designed to investigate dark energy, by detecting and monitoring approximately 2000 high-redshift supernovae between 2003 and 2008, using MegaPrime, a large CCD mosaic at the Canada-France-Hawaii Telescope. It also carries out detailed spectroscopy...
- Supernova Early Warning SystemSupernova Early Warning SystemThe SuperNova Early Warning System is a network of neutrino detectors designed to give early warning to astronomers in the event of a supernova in the Milky Way galaxy or a nearby galaxy such as the Large Magellanic Cloud or the Canis Major Dwarf Galaxy. Enormous numbers of neutrinos are produced...
- Monte Agliale Supernovae and Asteroid SurveyMonte Agliale Supernovae and Asteroid SurveyThe Monte Agliale Supernovae and Asteroid Survey is an offshoot of the Monte Agliale Supernovae Search , conducted from the Monte Agliale Astronomical Observatory....
- Supernova/Acceleration Probe
- Sloan Digital Sky Survey#Sloan Supernova Survey
- Supernova Cosmology Project
Black holes
Black hole
A black hole is a region of spacetime from which nothing, not even light, can escape. The theory of general relativity predicts that a sufficiently compact mass will deform spacetime to form a black hole. Around a black hole there is a mathematically defined surface called an event horizon that...
- Types
- Schwarzschild metricSchwarzschild metricIn Einstein's theory of general relativity, the Schwarzschild solution describes the gravitational field outside a spherical, uncharged, non-rotating mass such as a star, planet, or black hole. It is also a good approximation to the gravitational field of a slowly rotating body like the Earth or...
- Rotating black holeRotating black holeA rotating black hole is a black hole that possesses spin angular momentum.-Types of black holes:There are four known, exact, black hole solutions to Einstein's equations, which describe gravity in General Relativity. Two of these rotate...
- Charged black holeCharged black holeA charged black hole is a black hole that possesses electric charge. Since the electromagnetic repulsion in compressing an electrically charged mass is dramatically greater than the gravitational attraction , it is not expected that black holes with a significant electric charge will be formed in...
- Virtual black holeVirtual black holeIn quantum gravity, a virtual black hole is a black hole that exists temporarily as a result of a quantum fluctuation of spacetime. It is an example of quantum foam and is the gravitational analog of the virtual electron-positron pairs found in quantum electrodynamics...
- Schwarzschild metric
- Size
- Micro black holeMicro black holeMicro black holes are tiny black holes, also called quantum mechanical black holes or mini black holes, for which quantum mechanical effects play an important role....
- Extremal black holeExtremal black holeIn theoretical physics, an extremal black hole is a black hole with the minimal possible mass that can be compatible with a given charge and angular momentum . In other words, this is the smallest possible black hole that can exist while rotating at a given fixed constant speed.The concept of an...
(Black hole electronBlack hole electronIn physics, there is a speculative notion that if there were a black hole with the same mass and charge as an electron, it would share many of the properties of the electron including the magnetic moment and Compton wavelength. This idea is substantiated within a series of papers published by...
) - Stellar black holeStellar black holeA stellar black hole is a black hole formed by the gravitational collapse of a massive star. They have masses ranging from about 3 to several tens of solar masses...
- Intermediate-mass black holeIntermediate-mass black holeAn Intermediate-mass black hole is a black hole whose mass is significantly more than stellar black holes yet far less than supermassive black holes...
- Supermassive black holeSupermassive black holeA supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
- QuasarQuasarA quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
(Active galactic nucleusActive galactic nucleusAn active galactic nucleus is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion, and possibly all, of the electromagnetic spectrum. Such excess emission has been observed in the radio, infrared, optical, ultra-violet, X-ray and... - BlazarBlazarA blazar is a very compact quasar associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy...
)
- Micro black hole
- Formation
- Stellar evolutionStellar evolutionStellar evolution is the process by which a star undergoes a sequence of radical changes during its lifetime. Depending on the mass of the star, this lifetime ranges from only a few million years to trillions of years .Stellar evolution is not studied by observing the life of a single...
- Gravitational collapseGravitational collapseGravitational collapse is the inward fall of a body due to the influence of its own gravity. In any stable body, this gravitational force is counterbalanced by the internal pressure of the body, in the opposite direction to the force of gravity...
- Neutron starNeutron starA neutron star is a type of stellar remnant that can result from the gravitational collapse of a massive star during a Type II, Type Ib or Type Ic supernova event. Such stars are composed almost entirely of neutrons, which are subatomic particles without electrical charge and with a slightly larger...
(Template:neutron star) - Compact starCompact starIn astronomy, the term compact star is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes. These objects are all small for their mass...
(Quark starQuark starA quark star or strange star is a hypothetical type of exotic star composed of quark matter, or strange matter. These are ultra-dense phases of degenerate matter theorized to form inside particularly massive neutron stars.... - Exotic starExotic starAn exotic star is a compact star composed of something other than electrons, protons, and neutrons balanced against gravitational collapse by degeneracy pressure or other quantum properties...
) - Tolman–Oppenheimer–Volkoff limit
- White dwarfWhite dwarfA white dwarf, also called a degenerate dwarf, is a small star composed mostly of electron-degenerate matter. They are very dense; a white dwarf's mass is comparable to that of the Sun and its volume is comparable to that of the Earth. Its faint luminosity comes from the emission of stored...
(Template:white dwarf) - SupernovaSupernovaA supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
(Template:supernovae) - HypernovaHypernovaHypernova , also known as a type 1c Supernova, refers to an incredibly large star that collapses at the end of its lifespan...
- Gamma-ray burst
- Stellar evolution
- Properties
- Black hole thermodynamicsBlack hole thermodynamicsIn physics, black hole thermodynamics is the area of study that seeks to reconcile the laws of thermodynamics with the existence of black hole event horizons...
- Schwarzschild radiusSchwarzschild radiusThe Schwarzschild radius is the distance from the center of an object such that, if all the mass of the object were compressed within that sphere, the escape speed from the surface would equal the speed of light...
- M-sigma relationM-sigma relationThe M-sigma relation is an empirical correlation between the stellar velocity dispersion \sigma of a galaxy bulge and the mass M of the supermassive black hole atthe galaxy's center.The relation can be expressed mathematically as...
- Event horizonEvent horizonIn general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms it is defined as "the point of no return" i.e. the point at which the gravitational pull becomes so great as to make escape impossible. The most common case...
- Quasi-periodic oscillation
- Photon sphere
- ErgosphereErgosphereThe ergosphere is a region located outside a rotating black hole. Its name is derived from the Greek word ergon, which means “work”. It received this name because it is theoretically possible to extract energy and mass from the black hole in this region...
- Hawking radiationHawking radiationHawking radiation is a thermal radiation with a black body spectrum predicted to be emitted by black holes due to quantum effects. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974, and sometimes also after the physicist Jacob Bekenstein...
- Penrose processPenrose processThe Penrose process is a process theorised by Roger Penrose wherein energy can be extracted from a rotating black hole...
- Bondi accretionBondi accretionBondi Accretion is spherical accretion onto an object. It is generally used in the context of neutron star and black hole accretion for compact objects traveling through the interstellar medium...
- SpaghettificationSpaghettificationIn astrophysics, spaghettification is the vertical stretching and horizontal compression of objects into long thin shapes in a very strong gravitational field, and is caused by extreme tidal forces...
- Gravitational lensGravitational lensA gravitational lens refers to a distribution of matter between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer...
- Black hole thermodynamics
- Models
- Gravitational singularityGravitational singularityA gravitational singularity or spacetime singularity is a location where the quantities that are used to measure the gravitational field become infinite in a way that does not depend on the coordinate system...
(Penrose–Hawking singularity theorems) - Primordial black holePrimordial black holeA primordial black hole is a hypothetical type of black hole that is formed not by the gravitational collapse of a large star but by the extreme density of matter present during the universe's early expansion....
- GravastarGravastarA gravastar is an object hypothesized in astrophysics as an alternative to the black hole theory by Pawel Mazur and Emil Mottola. It results from assuming real, physical limitations on the formation of black holes...
- Dark star
- Dark energy starDark energy starA dark-energy star is a hypothetical compact astrophysical object, which a minority of physicists feel might constitute an alternative explanation for observations of astronomical black hole candidates. Dark energy is invisible to the human eye; however, it can be tracked with difficulty by...
- Black starBlack Star (semiclassical gravity)A black star is a gravitational object composed of matter. It is a theoretical alternative to the black hole concept from general relativity. The theoretical construct was created through the use of semiclassical gravity theory...
- Magnetospheric eternally collapsing objectMagnetospheric eternally collapsing objectMagnetospheric Eternally Collapsing Objects or MECOs are proposed alternatives to black holes advocated by Darryl Leiter and Stanley Robertson. They are a variant of eternally collapsing objects or ECOs proposed by Abhas Mitra in 1998. Mitra had devised an ostensive proof that black holes cannot...
- Fuzzball
- White holeWhite holeA white hole, in general relativity, is a hypothetical region of spacetime which cannot be entered from the outside, but from which matter and light may escape. In this sense it is the reverse of a black hole, which can be entered from the outside, but from which nothing, including light, may escape...
- Naked singularityNaked singularityIn general relativity, a naked singularity is a gravitational singularity, without an event horizon. In a black hole, there is a region around the singularity, the event horizon, where the gravitational force of the singularity is strong enough so that light cannot escape. Hence, the singularity...
- Ring singularityRing singularityRing singularity is a term used in general relativity to describe the altering gravitational singularity of a rotating black hole, or a Kerr black hole, so that the gravitational singularity becomes shaped like a ring.-Description of a ring-singularity:...
- Immirzi parameterImmirzi parameterThe Immirzi parameter is a numerical coefficient appearing in loop quantum gravity, a nonperturbative theory of quantum gravity. The Immirzi parameter measures the size of the quantum of area in Planck units...
- Membrane paradigmMembrane paradigmIn black hole theory, the black hole membrane paradigm is a useful "toy model" method or "engineering approach" for visualising and calculating the effects predicted by quantum mechanics for the exterior physics of black holes, without using quantum-mechanical principles or calculations...
- KugelblitzKugelblitz (astrophysics)In theoretical physics, a kugelblitz is a concentration of light so intense that it forms an event horizon and becomes self-trapped: according to general relativity, if we aim enough radiation into a region, the concentration of energy can warp spacetime enough for the region to become a black...
- WormholeWormholeIn physics, a wormhole is a hypothetical topological feature of spacetime that would be, fundamentally, a "shortcut" through spacetime. For a simple visual explanation of a wormhole, consider spacetime visualized as a two-dimensional surface. If this surface is folded along a third dimension, it...
- QuasistarQuasistarA quasi-star is a hypothetical type of extremely massive star that may have existed very early in the history of the Universe...
- Gravitational singularity
- Issues
- No-hair theorem
- Black hole information paradoxBlack hole information paradoxThe black hole information paradox results from the combination of quantum mechanics and general relativity. It suggests that physical information could disappear in a black hole, allowing many physical states to evolve into the same state...
- Cosmic censorship hypothesisCosmic censorship hypothesisThe weak and the strong cosmic censorship hypotheses are two mathematical conjectures about the structure of singularities arising in general relativity....
- Nonsingular black hole modelsNonsingular black hole modelsA nonsingular black hole model is a mathematical theory of black holes that avoids certain theoretical problems with the standard black hole model, including information loss and the unobservable nature of the black hole event horizon....
- Holographic principleHolographic principleThe holographic principle is a property of quantum gravity and string theories which states that the description of a volume of space can be thought of as encoded on a boundary to the region—preferably a light-like boundary like a gravitational horizon...
- Black hole complementarityBlack hole complementarityBlack hole complementarity is a conjectured solution to the black hole information paradox, proposed by Leonard Susskind and Gerard 't Hooft.Ever since Stephen Hawking suggested information is lost in evaporating black hole once it passes through the event horizon and is inevitably destroyed at the...
- Metrics
- Schwarzschild metricSchwarzschild metricIn Einstein's theory of general relativity, the Schwarzschild solution describes the gravitational field outside a spherical, uncharged, non-rotating mass such as a star, planet, or black hole. It is also a good approximation to the gravitational field of a slowly rotating body like the Earth or...
- Kerr metricKerr metricThe Kerr metric describes the geometry of empty spacetime around an uncharged axially-symmetric black-hole with an event horizon which is topologically a sphere. The Kerr metric is an exact solution of the Einstein field equations of general relativity; these equations are highly non-linear, which...
- Reissner–Nordström
- Kerr–Newman
- Schwarzschild metric
- Related
- List of black holes
- Timeline of black hole physicsTimeline of black hole physicsTimeline of black hole physics* 1640 — Ismael Bullialdus suggests an inverse-square gravitational force law* 1684 — Isaac Newton writes down his inverse-square Law of universal gravitation...
- Rossi X-ray Timing ExplorerRossi X-ray Timing ExplorerThe Rossi X-ray Timing Explorer is a satellite that observes the time structure of astronomical X-ray sources. The RXTE has three instruments—the Proportional Counter Array, the High-Energy X-ray Timing Experiment , and one instrument called the All Sky Monitor...
- Hypercompact stellar systemHypercompact stellar systemA hypercompact stellar system is a dense cluster of stars around a supermassive black hole that has been ejected from the centre of its host galaxy...
The 88 modern constellations
- AndromedaAndromeda (constellation)Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...
- AntliaAntliaAntlia is a constellation in the southern sky. Its name means "pump" and it specifically represents an air pump. The stars comprising Antlia are faint, and the constellation was not created until the 18th century...
- ApusApusApus is a faint constellation in the southern sky, first defined in the late 16th century. Its name means "no feet" in Greek, and it represents a bird-of-paradise . It is bordered by Triangulum Australe, Circinus, Musca, Chamaeleon, Octans, Pavo and Ara...
- AquariusAquarius (constellation)Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-bearer" or "cup-bearer", and its symbol is , a representation of water....
- AquilaAquila (constellation)Aquila is a stellar constellation. Its name is Latin for 'eagle' and it is commonly represented as such. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him....
- AraAra (constellation)Ara is a southern constellation situated between Scorpius and Triangulum Australe. Its name is Latin for "altar". Ara was one of the 48 Greek constellations described by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical...
- AriesAries (constellation)Aries is one of the constellations of the zodiac, located between Pisces to the west and Taurus to the east. Its name is Latin for ram, and its symbol is , representing a ram's horns...
- AurigaAuriga (constellation)Auriga is a constellation in the northern sky. Its name is Latin for 'charioteer' and its stars form a shape that has been associated with the pointed helmet of a charioteer. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains among the 88 modern...
- BoötesBoötesBoötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from the Greek Βοώτης, Boōtēs, meaning herdsman or plowman...
- CaelumCaelumCaelum is a faint constellation in the southern sky, introduced in the 18th century by Nicolas Louis de Lacaille. Its name means "the chisel" in Latin, and it was formerly known as Cæla Sculptoris, "the sculptor's chisel"...
- CamelopardalisCamelopardalisCamelopardalis is a large but faint constellation in the northern sky. The constellation was introduced in 1612 by Petrus Plancius. Some older astronomy books give an alternative spelling of the name, Camelopardus.-Etymology:...
- CancerCancer (constellation)Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...
- Canes VenaticiCanes VenaticiCanes Venatici is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for "hunting dogs", and the constellation is often depicted in illustrations as representing the dogs of Boötes the...
- Canis MajorCanis MajorCanis Major is one of the 88 modern constellations, and was included in the 2nd-century astronomer Ptolemy's 48 constellations. Its name is Latin for 'greater dog', and is commonly represented as one of the dogs following Orion the hunter...
- Canis MinorCanis MinorCanis Minor is a small constellation. It was included in the 2nd century astronomer Ptolemy's 48 constellations, and is still included among the 88 modern constellations...
- CapricornusCapricornusCapricornus is one of the constellations of the zodiac; it is often called Capricorn, especially when referring to the corresponding astrological sign. Its name is Latin for "horned male goat" or "goat horn", and it is commonly represented in the form of a sea-goat: a mythical creature that is half...
- CarinaCarina (constellation)Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was formerly part of the larger constellation of Argo Navis until that constellation was divided in three.-Stars:...
- CassiopeiaCassiopeia (constellation)Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...
- CentaurusCentaurusCentaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.-Stars:...
- CepheusCepheus (constellation)Cepheus is a constellation in the northern sky. It is named after Cepheus, King of Aethiopia in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
- CetusCetusCetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...
- ChamaeleonChamaeleonChamaeleon is a small constellation in the southern sky. It is named after the chameleon, a form of lizard. It was first defined in the sixteenth century.-History:...
- CircinusCircinusThe constellation Circinus is a small constellation in the southern sky, first defined in the 18th century. Its name is Latin for compass, referring to the drafting tool used for drawing circles; it should not be confused with Pyxis, a constellation that represents a mariner's...
- ColumbaColumba (constellation)Columba is a small, faint constellation created in the late sixteenth century. Its name is Latin for dove. It is located just south of Canis Major and Lepus.-History:...
- Coma BerenicesComa BerenicesComa Berenices is a traditional asterism that has since been defined as one of the 88 modern constellations. It is located near Leo, to which it formerly belonged, and accommodates the North Galactic Pole...
- Corona AustralisCorona AustralisCorona Australis or Corona Austrina is a constellation. Its name means "southern crown", and it contrasts with Corona Borealis, the northern crown...
- Corona BorealisCorona BorealisCorona Borealis is a small constellation in the northern sky. Its name is Latin for "northern crown", a name inspired by its shape; its main stars form a semicircular arc. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and remains one of the 88 modern...
- CorvusCorvus (constellation)Corvus is a small constellation in the southern sky. Its name is Latin for raven or crow. It includes only 11 stars visible to the naked eye...
- CraterCrater (constellation)Crater is a constellation. Its name is Latin for cup, and in Greek mythology it is identified with the cup of the god Apollo. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations...
- CruxCruxCrux is the smallest of the 88 modern constellations, but is one of the most distinctive. Its name is Latin for cross, and it is dominated by a cross-shaped asterism that is commonly known as the Southern Cross.-Visibility:...
- CygnusCygnus (constellation)Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...
- DelphinusDelphinusDelphinus is a constellation in the northern sky, close to the celestial equator. Its name is Latin for dolphin. Delphinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains among the 88 modern constellations recognized by the International Astronomical...
- DoradoDoradoDorado is a constellation in the southern sky. It was created in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish , which is known as dorado in Spanish, although it has also been depicted as a swordfish...
- DracoDraco (constellation)Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...
- EquuleusEquuleusEquuleus is a constellation. Its name is Latin for 'little horse', a foal. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is the second smallest of the modern constellations , spanning only 72 square degrees...
- EridanusEridanus (constellation)Eridanus is a constellation. It is represented as a river; its name is the Ancient Greek name for the Po River. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is the sixth largest of the modern...
- FornaxFornaxFornax is a constellation in the southern sky. Its name is Latin for furnace. It was created in the 18th century and is now one of the 88 modern constellations.-History:Fornax was formed by Nicolas Louis de Lacaille in 1756...
- GeminiGemini (constellation)Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...
- GrusGrus (constellation)Grus is a constellation in the southern sky. Its name is Latin for the crane, a species of bird. It was introduced in the late sixteenth century.-History:The stars that form Grus were originally considered part of Piscis Austrinus...
- HerculesHercules (constellation)Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
- HorologiumHorologiumHorologium is a small and faint constellation in the southern sky . Its name is Latin for clock. It was created in the 18th century by Abbé Nicolas Louis de Lacaille, who originally named it Horologium Oscillitorium after the pendulum clock to honour its inventor, Christiaan Huygens...
- HydraHydra (constellation)Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...
- HydrusHydrusHydrus is a small constellation in the southern sky, created in the sixteenth century. Its name means "male water snake", and it should not be confused with Hydra, a much larger constellation which represents a female water snake.-History:...
- IndusIndus (constellation)Indus is a constellation in the southern sky. Created in the sixteenth century, it represents an Indian, a word that could refer at the time to any native of Asia or the Americas.-Notable features:...
- LacertaLacertaLacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was created in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a "W" shape similar to that of Cassiopeia, and it is thus...
- LeoLeo (constellation)Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...
- Leo MinorLeo MinorLeo Minor is a small and faint constellation. Its name means "the smaller lion", in contrast to Leo, the larger lion. Its brightest stars form a rough triangle, and it lies between the larger and more recognizable Ursa Major and Leo...
- LepusLepus (constellation)Lepus is a constellation lying just south of the celestial equator, immediately south of Orion. Its name is Latin for hare. Although the hare does not represent any particular figure in Greek mythology, Lepus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it...
- LibraLibra (constellation)Libra is a constellation of the zodiac. Its name is Latin for weighing scales, and its symbol is . It is fairly faint, with no first magnitude stars, and lies between Virgo to the west and Scorpius to the east.-Notable features:]...
- LupusLupus (constellation)Lupus is a constellation in the southern sky. Its name is Latin for wolf. Lupus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations...
- LynxLynx (constellation)Lynx is a constellation in the northern sky, introduced in the 17th century by Johannes Hevelius. It is named after the lynx, a genus of cat. It is a very faint constellation; its brightest stars form a zigzag line.-History:...
- LyraLyraLyra is a small constellation. It is one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations recognized by the International Astronomical Union. Its principal star, Vega — a corner of the Summer Triangle — is one of the brightest...
- MensaMensa (constellation)Mensa is a constellation in the southern sky, created in the 18th century. Its name is Latin for table. It covers a keystone-shaped wedge of sky stretching from approximately 4h to 7.5h of right ascension, and −71 to −85.5 degrees of declination. Other than the south polar constellation...
- MicroscopiumMicroscopiumMicroscopium is a small constellation in the southern sky, created in the 18th century by Nicolas Louis de Lacaille. Its name is Latin for microscope. Its stars are very faint and hardly visible from most of the non-tropical northern hemisphere.-References:...
- MonocerosMonocerosMonoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east...
- MuscaMuscaMusca is one of the minor southern constellations. The constellation was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 in Amsterdam by...
- NormaNorma (constellation)Norma is a small and inconspicuous constellation in the southern hemisphere between Scorpius and Centaurus. Its name is Latin for normal, referring to a right angle, and is variously considered to represent a rule, a carpenter's square, a set square or a level....
- OctansOctansOctans is a faint constellation the southern sky. Its name is Latin for the eighth part of a circle, but it is named after the octant, a navigational instrument. The constellation was devised by Nicolas Louis de Lacaille in the eighteenth century....
- OphiuchusOphiuchusOphiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...
- OrionOrion (constellation)Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...
- PavoPavo (constellation)Pavo is a constellation in the southern sky. Its name is Latin for peacock. It is one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 in...
- PegasusPegasus (constellation)Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
- PerseusPerseus (constellation)Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...
- PhoenixPhoenix (constellation)Phoenix is a minor constellation in the southern sky. It is named after the Phoenix, a mythical bird. It is faint: there are only two stars in the whole constellation which are brighter than magnitude 5.0...
- PictorPictorPictor is a small and faint constellation in the southern sky , located between the brilliant star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, but it is in fact an abbreviation of its original name Equuleus Pictoris, the 'painter's easel', and it is normally represented...
- PiscesPisces (constellation)Pisces is a constellation of the zodiac. Its name is the Latin plural for fish, and its symbol is . It lies between Aquarius to the west and Aries to the east...
- Piscis AustrinusPiscis AustrinusPiscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish" in contrast with the larger constellation Pisces, which represents a pair of fishes. Prior to the 20th century, it was also known as Piscis Notius...
- PuppisPuppisPuppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...
- PyxisPyxisPyxis is a small and faint constellation in the southern sky. Its name is Latin for a mariner's compass...
- ReticulumReticulumReticulum is a small, faint constellation in the southern sky. Its name is Latin for a small net, or reticle—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions...
- SagittaSagittaSagitta is a constellation. Its name is Latin for "arrow", and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations...
- SagittariusSagittarius (constellation)Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...
- ScorpiusScorpiusScorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...
- SculptorSculptor (constellation)Sculptor is a small and faint constellation in the southern sky. It represents a sculptor. It was introduced by Nicolas Louis de Lacaille in the 18th century. He originally named it Apparatus Sculptoris , but the name was later shortened.-Notable features:No stars brighter than 3rd magnitude are...
- ScutumScutumScutum is a small constellation introduced in the seventeenth century. Its name is Latin for shield.-History:Scutum is the only constellation that owes its name to a non-classical historical figure...
- SerpensSerpensSerpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....
- SextansSextansSextans is a minor equatorial constellation which was introduced in 1687 by Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations.-Notable features:...
- TaurusTaurus (constellation)Taurus is one of the constellations of the zodiac. Its name is a Latin word meaning 'bull', and its astrological symbol is a stylized bull's head:...
- TelescopiumTelescopiumTelescopium is a minor southern constellation created in the 18th century by Nicolas Louis de Lacaille, a French astronomer and student of the southern skies. Its name is a Latinized form of the Greek word for telescope....
- TriangulumTriangulumTriangulum is a small constellation in the northern sky. Its name is Latin for triangle, and it should not be confused with Triangulum Australe in the southern sky. Its name derives from its three brightest stars, of third and fourth magnitude, which form a nearly isosceles long and narrow triangle...
- Triangulum AustraleTriangulum AustraleTriangulum Australe is a small constellation in the southern sky, created in the sixteenth century. Its name is Latin for 'the southern triangle', which distinguishes it from Triangulum in the northern sky...
- TucanaTucanaTucana is a constellation in the southern sky, created in the late sixteenth century. Its name is Latin for the toucan, a South American bird.-History:...
- Ursa MajorUrsa MajorUrsa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...
- Ursa MinorUrsa MinorUrsa Minor , also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, whence the name Little Dipper...
- VelaVela (constellation)Vela is a constellation in the southern sky. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis.-Stars:...
- VirgoVirgo (constellation)Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...
- VolansVolansVolans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans...
- VulpeculaVulpeculaVulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle .-Stars:There are no stars brighter than 4th magnitude in...
The 48 constellations listed by PtolemyPtolemyClaudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
after 150 AD
- AndromedaAndromeda (constellation)Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...
- AquariusAquarius (constellation)Aquarius is a constellation of the zodiac, situated between Capricornus and Pisces. Its name is Latin for "water-bearer" or "cup-bearer", and its symbol is , a representation of water....
- AquilaAquila (constellation)Aquila is a stellar constellation. Its name is Latin for 'eagle' and it is commonly represented as such. In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him....
- AraAra (constellation)Ara is a southern constellation situated between Scorpius and Triangulum Australe. Its name is Latin for "altar". Ara was one of the 48 Greek constellations described by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical...
- Argo NavisArgo NavisArgo Navis was a large constellation in the southern sky that has since been divided into three constellations. It represented the Argo, the ship used by Jason and the Argonauts in Greek mythology...
- AriesAries (constellation)Aries is one of the constellations of the zodiac, located between Pisces to the west and Taurus to the east. Its name is Latin for ram, and its symbol is , representing a ram's horns...
- AurigaAuriga (constellation)Auriga is a constellation in the northern sky. Its name is Latin for 'charioteer' and its stars form a shape that has been associated with the pointed helmet of a charioteer. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains among the 88 modern...
- BoötesBoötesBoötes is a constellation in the northern sky, located between 0° and +60° declination, and 13 and 16 hours of right ascension on the celestial sphere. The name comes from the Greek Βοώτης, Boōtēs, meaning herdsman or plowman...
- CancerCancer (constellation)Cancer is one of the twelve constellations of the zodiac. Its name is Latin for crab and it is commonly represented as such. Its symbol is . Cancer is small and its stars are faint...
- Canis MajorCanis MajorCanis Major is one of the 88 modern constellations, and was included in the 2nd-century astronomer Ptolemy's 48 constellations. Its name is Latin for 'greater dog', and is commonly represented as one of the dogs following Orion the hunter...
- Canis MinorCanis MinorCanis Minor is a small constellation. It was included in the 2nd century astronomer Ptolemy's 48 constellations, and is still included among the 88 modern constellations...
- CapricornusCapricornusCapricornus is one of the constellations of the zodiac; it is often called Capricorn, especially when referring to the corresponding astrological sign. Its name is Latin for "horned male goat" or "goat horn", and it is commonly represented in the form of a sea-goat: a mythical creature that is half...
- CassiopeiaCassiopeia (constellation)Cassiopeia is a constellation in the northern sky, named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty. Cassiopea was one of the 48 constellations listed by the 2nd century Greek astronomer Ptolemy, and it remains one of the 88 modern constellations today...
- CentaurusCentaurusCentaurus is a bright constellation in the southern sky. One of the largest constellations, Centaurus was included among the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations.-Stars:...
- CepheusCepheus (constellation)Cepheus is a constellation in the northern sky. It is named after Cepheus, King of Aethiopia in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
- CetusCetusCetus is a constellation. Its name refers to Cetus, a sea monster in Greek mythology, although it is often called 'the whale' today. Cetus is located in the region of the sky that contains other water-related constellations such as Aquarius, Pisces, and Eridanus.-Ecliptic:Although Cetus is not...
- Corona AustralisCorona AustralisCorona Australis or Corona Austrina is a constellation. Its name means "southern crown", and it contrasts with Corona Borealis, the northern crown...
- Corona BorealisCorona BorealisCorona Borealis is a small constellation in the northern sky. Its name is Latin for "northern crown", a name inspired by its shape; its main stars form a semicircular arc. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and remains one of the 88 modern...
- CorvusCorvus (constellation)Corvus is a small constellation in the southern sky. Its name is Latin for raven or crow. It includes only 11 stars visible to the naked eye...
- CraterCrater (constellation)Crater is a constellation. Its name is Latin for cup, and in Greek mythology it is identified with the cup of the god Apollo. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations...
- CygnusCygnus (constellation)Cygnus is a northern constellation lying on the plane of the Milky Way. Its name is the Latinized Hellenic word for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross...
- DelphinusDelphinusDelphinus is a constellation in the northern sky, close to the celestial equator. Its name is Latin for dolphin. Delphinus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains among the 88 modern constellations recognized by the International Astronomical...
- DracoDraco (constellation)Draco is a constellation in the far northern sky. Its name is Latin for dragon. Draco is circumpolar for many observers in the northern hemisphere...
- EquuleusEquuleusEquuleus is a constellation. Its name is Latin for 'little horse', a foal. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations. It is the second smallest of the modern constellations , spanning only 72 square degrees...
- EridanusEridanus (constellation)Eridanus is a constellation. It is represented as a river; its name is the Ancient Greek name for the Po River. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations. It is the sixth largest of the modern...
- GeminiGemini (constellation)Gemini is one of the constellations of the zodiac. It was one of the 48 constellations described by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations today. Its name is Latin for "twins", and it is associated with the twins Castor and Pollux in Greek mythology...
- HerculesHercules (constellation)Hercules is a constellation named after Hercules, the Roman mythological hero adapted from the Greek hero Heracles. Hercules was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations today...
- HydraHydra (constellation)Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees. It has a long history, having been included among the 48 constellations listed by the 2nd century astronomer Ptolemy. It is commonly represented as a water snake...
- LeoLeo (constellation)Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is . Leo lies between dim Cancer to the west and Virgo to the east.-Stars:...
- LepusLepus (constellation)Lepus is a constellation lying just south of the celestial equator, immediately south of Orion. Its name is Latin for hare. Although the hare does not represent any particular figure in Greek mythology, Lepus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it...
- LibraLibra (constellation)Libra is a constellation of the zodiac. Its name is Latin for weighing scales, and its symbol is . It is fairly faint, with no first magnitude stars, and lies between Virgo to the west and Scorpius to the east.-Notable features:]...
- LupusLupus (constellation)Lupus is a constellation in the southern sky. Its name is Latin for wolf. Lupus was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and it remains one of the 88 modern constellations...
- LyraLyraLyra is a small constellation. It is one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations recognized by the International Astronomical Union. Its principal star, Vega — a corner of the Summer Triangle — is one of the brightest...
- OphiuchusOphiuchusOphiuchus is a large constellation located around the celestial equator. Its name is from the Greek "serpent-bearer", and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 2nd-century...
- OrionOrion (constellation)Orion, often referred to as The Hunter, is a prominent constellation located on the celestial equator and visible throughout the world. It is one of the most conspicuous, and most recognizable constellations in the night sky...
- PegasusPegasus (constellation)Pegasus is a constellation in the northern sky, named after the winged horse Pegasus in Greek mythology. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations.-Stars:...
- PerseusPerseus (constellation)Perseus is a constellation in the northern sky, named after the Greek hero Perseus. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations defined by the International Astronomical Union...
- PiscesPisces (constellation)Pisces is a constellation of the zodiac. Its name is the Latin plural for fish, and its symbol is . It lies between Aquarius to the west and Aries to the east...
- Piscis AustrinusPiscis AustrinusPiscis Austrinus is a constellation in the southern celestial hemisphere. The name is Latin for "the southern fish" in contrast with the larger constellation Pisces, which represents a pair of fishes. Prior to the 20th century, it was also known as Piscis Notius...
- SagittaSagittaSagitta is a constellation. Its name is Latin for "arrow", and it should not be confused with the larger constellation Sagittarius, the archer. Although ancient, it is insignificant, for it has no star brighter than the 4th magnitude and is the third smallest of all constellations...
- SagittariusSagittarius (constellation)Sagittarius is a constellation of the zodiac, the one containing the galactic center. Its name is Latin for the archer, and its symbol is , a stylized arrow. Sagittarius is commonly represented as a centaur drawing a bow...
- ScorpiusScorpiusScorpius, sometimes known as Scorpio, is one of the constellations of the zodiac. Its name is Latin for scorpion, and its symbol is . It lies between Libra to the west and Sagittarius to the east...
- SerpensSerpensSerpens is a constellation of the northern hemisphere. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy and it remains one of the 88 modern constellations defined by the International Astronomical Union....
- TaurusTaurus (constellation)Taurus is one of the constellations of the zodiac. Its name is a Latin word meaning 'bull', and its astrological symbol is a stylized bull's head:...
- TriangulumTriangulumTriangulum is a small constellation in the northern sky. Its name is Latin for triangle, and it should not be confused with Triangulum Australe in the southern sky. Its name derives from its three brightest stars, of third and fourth magnitude, which form a nearly isosceles long and narrow triangle...
- Ursa MajorUrsa MajorUrsa Major , also known as the Great Bear, is a constellation visible throughout the year in most of the northern hemisphere. It can best be seen in April...
- Ursa MinorUrsa MinorUrsa Minor , also known as the Little Bear, is a constellation in the northern sky. Like the Great Bear, the tail of the Little Bear may also be seen as the handle of a ladle, whence the name Little Dipper...
- VirgoVirgo (constellation)Virgo is one of the constellations of the zodiac. Its name is Latin for virgin, and its symbol is . Lying between Leo to the west and Libra to the east, it is the second largest constellation in the sky...
The 41 additional constellations added in the 16th–17th c.
- Vespucci or Corsalius early 16c: CruxCruxCrux is the smallest of the 88 modern constellations, but is one of the most distinctive. Its name is Latin for cross, and it is dominated by a cross-shaped asterism that is commonly known as the Southern Cross.-Visibility:...
- Triangulum AustraleTriangulum AustraleTriangulum Australe is a small constellation in the southern sky, created in the sixteenth century. Its name is Latin for 'the southern triangle', which distinguishes it from Triangulum in the northern sky...
▶ Vopel 1536: Coma BerenicesComa BerenicesComa Berenices is a traditional asterism that has since been defined as one of the 88 modern constellations. It is located near Leo, to which it formerly belonged, and accommodates the North Galactic Pole...
▶ Keyser & de Houtman 1596: ApusApusApus is a faint constellation in the southern sky, first defined in the late 16th century. Its name means "no feet" in Greek, and it represents a bird-of-paradise . It is bordered by Triangulum Australe, Circinus, Musca, Chamaeleon, Octans, Pavo and Ara... - ChamaeleonChamaeleonChamaeleon is a small constellation in the southern sky. It is named after the chameleon, a form of lizard. It was first defined in the sixteenth century.-History:...
- DoradoDoradoDorado is a constellation in the southern sky. It was created in the late 16th century and is now one of the 88 modern constellations. Its name refers to the dolphinfish , which is known as dorado in Spanish, although it has also been depicted as a swordfish...
- GrusGrus (constellation)Grus is a constellation in the southern sky. Its name is Latin for the crane, a species of bird. It was introduced in the late sixteenth century.-History:The stars that form Grus were originally considered part of Piscis Austrinus...
- HydrusHydrusHydrus is a small constellation in the southern sky, created in the sixteenth century. Its name means "male water snake", and it should not be confused with Hydra, a much larger constellation which represents a female water snake.-History:...
- IndusIndus (constellation)Indus is a constellation in the southern sky. Created in the sixteenth century, it represents an Indian, a word that could refer at the time to any native of Asia or the Americas.-Notable features:...
- MuscaMuscaMusca is one of the minor southern constellations. The constellation was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 in Amsterdam by...
- PavoPavo (constellation)Pavo is a constellation in the southern sky. Its name is Latin for peacock. It is one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm diameter celestial globe published in 1597 in...
- PhoenixPhoenix (constellation)Phoenix is a minor constellation in the southern sky. It is named after the Phoenix, a mythical bird. It is faint: there are only two stars in the whole constellation which are brighter than magnitude 5.0...
- TucanaTucanaTucana is a constellation in the southern sky, created in the late sixteenth century. Its name is Latin for the toucan, a South American bird.-History:...
- VolansVolansVolans is a constellation in the southern sky. It represents a flying fish; its name is a shortened form of its original name, Piscis Volans...
▶ Plancius 1613: CamelopardalisCamelopardalisCamelopardalis is a large but faint constellation in the northern sky. The constellation was introduced in 1612 by Petrus Plancius. Some older astronomy books give an alternative spelling of the name, Camelopardus.-Etymology:... - ColumbaColumba (constellation)Columba is a small, faint constellation created in the late sixteenth century. Its name is Latin for dove. It is located just south of Canis Major and Lepus.-History:...
- MonocerosMonocerosMonoceros is a faint constellation on the celestial equator. Its name is Greek for unicorn. Its definition is attributed to the 17th-century Dutch cartographer Petrus Plancius. It is bordered by Orion to the west, Gemini to the north, Canis Major to the south and Hydra to the east...
▶ Habrecht 1621: ReticulumReticulumReticulum is a small, faint constellation in the southern sky. Its name is Latin for a small net, or reticle—a net of crosshairs at the focus of a telescope eyepiece that is used to measure star positions...
▶ Hevelius 1683: Canes VenaticiCanes VenaticiCanes Venatici is one of the 88 official modern constellations. It is a small northern constellation that was created by Johannes Hevelius in the 17th century. Its name is Latin for "hunting dogs", and the constellation is often depicted in illustrations as representing the dogs of Boötes the... - LacertaLacertaLacerta is one of the 88 modern constellations defined by the International Astronomical Union. Its name is Latin for lizard. A small, faint constellation, it was created in 1687 by the astronomer Johannes Hevelius. Its brightest stars form a "W" shape similar to that of Cassiopeia, and it is thus...
- Leo MinorLeo MinorLeo Minor is a small and faint constellation. Its name means "the smaller lion", in contrast to Leo, the larger lion. Its brightest stars form a rough triangle, and it lies between the larger and more recognizable Ursa Major and Leo...
- LynxLynx (constellation)Lynx is a constellation in the northern sky, introduced in the 17th century by Johannes Hevelius. It is named after the lynx, a genus of cat. It is a very faint constellation; its brightest stars form a zigzag line.-History:...
- ScutumScutumScutum is a small constellation introduced in the seventeenth century. Its name is Latin for shield.-History:Scutum is the only constellation that owes its name to a non-classical historical figure...
- SextansSextansSextans is a minor equatorial constellation which was introduced in 1687 by Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations.-Notable features:...
- VulpeculaVulpeculaVulpecula is a faint constellation in the northern sky. Its name is Latin for "little fox", although it is commonly known simply as the fox. It was identified in the seventeenth century, and is located in the middle of the Summer Triangle .-Stars:There are no stars brighter than 4th magnitude in...
▶ de Lacaille 1763: AntliaAntliaAntlia is a constellation in the southern sky. Its name means "pump" and it specifically represents an air pump. The stars comprising Antlia are faint, and the constellation was not created until the 18th century... - CaelumCaelumCaelum is a faint constellation in the southern sky, introduced in the 18th century by Nicolas Louis de Lacaille. Its name means "the chisel" in Latin, and it was formerly known as Cæla Sculptoris, "the sculptor's chisel"...
- CarinaCarina (constellation)Carina is a constellation in the southern sky. Its name is Latin for the keel of a ship, and it was formerly part of the larger constellation of Argo Navis until that constellation was divided in three.-Stars:...
- CircinusCircinusThe constellation Circinus is a small constellation in the southern sky, first defined in the 18th century. Its name is Latin for compass, referring to the drafting tool used for drawing circles; it should not be confused with Pyxis, a constellation that represents a mariner's...
- FornaxFornaxFornax is a constellation in the southern sky. Its name is Latin for furnace. It was created in the 18th century and is now one of the 88 modern constellations.-History:Fornax was formed by Nicolas Louis de Lacaille in 1756...
- HorologiumHorologiumHorologium is a small and faint constellation in the southern sky . Its name is Latin for clock. It was created in the 18th century by Abbé Nicolas Louis de Lacaille, who originally named it Horologium Oscillitorium after the pendulum clock to honour its inventor, Christiaan Huygens...
- MensaMensa (constellation)Mensa is a constellation in the southern sky, created in the 18th century. Its name is Latin for table. It covers a keystone-shaped wedge of sky stretching from approximately 4h to 7.5h of right ascension, and −71 to −85.5 degrees of declination. Other than the south polar constellation...
- MicroscopiumMicroscopiumMicroscopium is a small constellation in the southern sky, created in the 18th century by Nicolas Louis de Lacaille. Its name is Latin for microscope. Its stars are very faint and hardly visible from most of the non-tropical northern hemisphere.-References:...
- NormaNorma (constellation)Norma is a small and inconspicuous constellation in the southern hemisphere between Scorpius and Centaurus. Its name is Latin for normal, referring to a right angle, and is variously considered to represent a rule, a carpenter's square, a set square or a level....
- OctansOctansOctans is a faint constellation the southern sky. Its name is Latin for the eighth part of a circle, but it is named after the octant, a navigational instrument. The constellation was devised by Nicolas Louis de Lacaille in the eighteenth century....
- PictorPictorPictor is a small and faint constellation in the southern sky , located between the brilliant star Canopus and the Large Magellanic Cloud. Its name is Latin for painter, but it is in fact an abbreviation of its original name Equuleus Pictoris, the 'painter's easel', and it is normally represented...
- PuppisPuppisPuppis is a constellation in the southern sky. Its name is the Latin word for the poop deck of a ship, and Puppis represents the deck of the ship and its deckhouses...
- PyxisPyxisPyxis is a small and faint constellation in the southern sky. Its name is Latin for a mariner's compass...
- SculptorSculptor (constellation)Sculptor is a small and faint constellation in the southern sky. It represents a sculptor. It was introduced by Nicolas Louis de Lacaille in the 18th century. He originally named it Apparatus Sculptoris , but the name was later shortened.-Notable features:No stars brighter than 3rd magnitude are...
- TelescopiumTelescopiumTelescopium is a minor southern constellation created in the 18th century by Nicolas Louis de Lacaille, a French astronomer and student of the southern skies. Its name is a Latinized form of the Greek word for telescope....
- VelaVela (constellation)Vela is a constellation in the southern sky. Its name is Latin for the sails of a ship, and it was originally part of a larger constellation, the ship Argo Navis, which was later divided into three parts, the others being Carina and Puppis.-Stars:...
Obsolete constellations including Ptolemy's Argo Navis
Obsolete constellations
Former constellations
Former constellations are constellations that are no longer recognized by the International Astronomical Union for various reasons. Many of these constellations existed for long periods of time, even centuries in many cases, which means they still have a large historical value and can be found on...
including Ptolemy's Argo Navis
Anser
- AntinousAntinous (constellation)Antinous is an obsolete constellation no longer in use by astronomers, having been merged into Aquila, which it bordered to the North.The constellation was created by the emperor Hadrian in 132. According to legend, Hadrian was told by an oracle that only death of his most beloved person would save...
- Argo NavisArgo NavisArgo Navis was a large constellation in the southern sky that has since been divided into three constellations. It represented the Argo, the ship used by Jason and the Argonauts in Greek mythology...
- Asterion
- Cancer MinorCancer Minor (constellation)Cancer Minor, Latin: lesser crab, was a constellation composed from a stars in Gemini adjacent to Cancer. The constellation was introduced in 1612 by Petrus Plancius....
- CerberusCerberus (constellation)Cerberus was a constellation created by Hevelius. It was depicted as a three-headed snake that Hercules is holding in his hand. The constellation is no longer in use. This constellation "figure typified the serpent .....
- Chara
- Custos MessiumCustos MessiumCustos Messium was a constellation created by Jérôme Lalande in 1775 to honor Charles Messier. It was located between the constellations of Camelopardalis, Cassiopeia and Cepheus. It is no longer recognized.-Reference:...
- FelisFelis (constellation)Felis was a constellation created by Jérôme Lalande in 1799. He chose the name partially because, as a cat lover, he felt sorry that there was not yet a cat among the constellations...
- Frederici Honores/Gloria FredericiFrederici HonoresFrederici Honores or Honores Friderici or Gloria Frederica was a constellation created by Johann Bode in 1787 to honor Frederick the Great, the king of Prussia who had died in the previous year. It was located in a region between the constellations Cepheus, Andromeda, Cassiopeia and Cygnus...
- GallusGallus (constellation)Gallus was a constellation introduced in 1612 by Petrus Plancius.It was in the northern part of what is now Puppis. It was not adopted in the atlases of Johannes Hevelius, John Flamsteed and Johann Bode and fell into disuse....
- Globus AerostaticusGlobus AerostaticusGlobus Aerostaticus was a constellation created by Jérôme Lalande in 1798. It was located east from the constellation Microscopium. It is no longer in use.-External links:...
- JordanusJordanus (constellation)Jordanus was a constellation introduced in 1612 by Petrus Plancius.One end was in Canes Venatici and then it flowed through Leo Minor and Lynx and ended near Camelopardalis. This constellation was not adopted in the atlases of Johann Bode and fell into disuse....
- Lochium FunisLochium FunisLochium Funis was a constellation created by Johann Bode from the stars which Nicolas Louis de Lacaille created the constellation Pyxis. It was never used by other astronomers.-External links:...
- Machina ElectricaMachina ElectricaMachina Electrica was a constellation created by Johann Bode in 1800. He created it from a southern part of constellation Cetus. It was never popular and is no longer in use.-External links:* , by * by Ian Ridpath...
- MalusMalus (constellation)Malus was a sectional asterism in the former constellation Argo Navis. Its stars were incorporated into the new constellation Pyxis by Nicolas Louis de Lacaille.-External links:...
- Mons MaenalusMons MaenalusMons Maenalus was a constellation created by Johannes Hevelius. It was located between the constellations of Boötes and Virgo, and depicts a mountain in Greece that the herdsman is stepping upon. It was never popular and is no longer in use...
- Musca BorealisMusca BorealisMusca Borealis was a constellation located between the constellations of Aries and Perseus.It was first described as such by Hevelius in his catalogue of 1690, to distinguish it from the southern fly, Musca Australis....
- Noctua
- Officina TypographicaOfficina TypographicaOfficina Typographica was a constellation located east of Sirius. It was created by Johann Bode in the late eighteenth century, and included in his star atlas Uranographia...
- PolophylaxPolophylaxPolophylax was a southern constellation that laid where Tucana and Grus now are.It was introduced by Petrus Plancius in the small celestial planispheres on his large wall map of 1592...
- Psalterium Georgianum/Harpa GeorgiiPsalterium GeorgiiPsalterium Georgii was a constellation created by Maximilian Hell in 1789 to honor George III of Great Britain. It was created from northern stars in Eridanus and was located next to the constellation Taurus, so as to include 10 Tauri...
- Quadrans MuralisQuadrans MuralisQuadrans Muralis was a constellation created by Jérôme Lalande in 1795. It was located between the constellations of Boötes and Draco, near the tail of Ursa Major...
- Ramus PomiferRamus PomiferRamus Pomifer was a constellation located between Hercules and Lyra.It was depicted in the form of three serpents wrapped around a branch held in Hercules' left hand....
- Robur CarolinumRobur CarolinumRobur Carolinum was a constellation created by the English astronomer Sir Edmond Halley in 1679. The name refers to the oak where Charles II was said to have hidden from the troops of Oliver Cromwell after the Battle of Worcester. It was located between the constellations of Crux and Carina...
- Sceptrum BrandenburgicumSceptrum BrandenburgicumSceptrum Brandenburgicum was a constellation created in 1688 by Gottfried Kirch, astronomer of the Prussian Royal Society of Sciences. It represented the scepter used by the royal family of the Brandenburgs. It was located west from the constellation of Lepus...
- Sceptrum et Manus IustitiaeSceptrum et Manus IustitiaeSceptrum et Manus Iustitiae was a constellation created by Augustin Royer in 1679 to honor king Louis XIV of France...
- SolariumSolarium (constellation)Solarium was a constellation located between the constellations of Horologium, Dorado and Hydrus. It occurred in the 1835 star map of Elijah Hinsdale Burritt. The origin of the constellation is unknown, but it is possible that it just occurred in his star map...
- Rangifer/Tarandus
- Taurus PoniatoviiTaurus PoniatoviiTaurus Poniatovii was a constellation created by Marcin Odlanicki Poczobutt in 1777 to honor Stanislaus Poniatowski, king of Poland. It consisted of stars that are today considered part of Ophiuchus and Aquila...
- Telescopium HerscheliiTelescopium HerscheliiTelescopium Herschelii was a constellation created by Maximilian Hell in 1789 to honor the famous English astronomer Sir William Herschel's discovery of the planet Uranus. It was located in the constellation Auriga near the border to Lynx and Gemini. It is no longer in use.-External links:* *...
- Testudo
- TigrisRiver Tigris (constellation)River Tigris or Tigris was a constellation, introduced in 1612 by Petrus Plancius. One end was near the shoulder of Ophiuchus and the other was near Pegasus, and in between it passed through the area now occupied by Vulpecula, flowing between Cygnus and Aquila...
- Triangulum Minus
- Turdus SolitariusTurdus SolitariusTurdus Solitarius was a constellation created by Pierre Charles Lemonnier in 1776 from stars of Hydra's tail. It was replaced by another constellation, Noctua...
- VespaVespa (constellation)Vespa was the name used by Jakob Bartsch in 1624 for a constellation, now obsolete, that was originally called Apes by Petrus Plancius when he created it in 1612. It was made up of a small group of stars, located between the constellations of Aries and Perseus...
- Vultur cadens
- Vultur volans
Clusters and nebulae
- Interstellar matter –
- NebulaNebulaA nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...
– - Crab NebulaCrab NebulaThe Crab Nebula is a supernova remnant and pulsar wind nebula in the constellation of Taurus...
– - H I regionH I regionAn H I region is an interstellar cloud composed of neutral atomic hydrogen , in addition to the local abundance of helium and other elements. These regions are non-luminous, save for emission of the 21-cm region spectral line. This line has a very low transition probability, so requires large...
– - H II regionH II regionAn H II region is a large, low-density cloud of partially ionized gas in which star formation has recently taken place. The short-lived, blue stars forged in these regions emit copious amounts of ultraviolet light, ionizing the surrounding gas...
– - Orion nebulaOrion NebulaThe Orion Nebula is a diffuse nebula situated south of Orion's Belt. It is one of the brightest nebulae, and is visible to the naked eye in the night sky. M42 is located at a distance of and is the closest region of massive star formation to Earth. The M42 nebula is estimated to be 24 light...
– - Planetary nebulaPlanetary nebulaA planetary nebula is an emission nebula consisting of an expanding glowing shell of ionized gas ejected during the asymptotic giant branch phase of certain types of stars late in their life...
– - PleiadesPleiades (star cluster)In astronomy, the Pleiades, or Seven Sisters , is an open star cluster containing middle-aged hot B-type stars located in the constellation of Taurus. It is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky...
–
Galaxies
- GalaxyGalaxyA galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
– - Andromeda GalaxyAndromeda GalaxyThe Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...
– - Magellanic CloudsMagellanic CloudsThe two Magellanic Clouds are irregular dwarf galaxies visible in the southern hemisphere, which are members of our Local Group and are orbiting our Milky Way galaxy...
– - QuasarQuasarA quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
–
Cosmology
- Big BangBig BangThe Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...
– - Cosmic microwave background –
- CosmosCosmosIn the general sense, a cosmos is an orderly or harmonious system. It originates from the Greek term κόσμος , meaning "order" or "ornament" and is antithetical to the concept of chaos. Today, the word is generally used as a synonym of the word Universe . The word cosmos originates from the same root...
– - Dark matterDark matterIn astronomy and cosmology, dark matter is matter that neither emits nor scatters light or other electromagnetic radiation, and so cannot be directly detected via optical or radio astronomy...
– - Cosmic distance ladderCosmic distance ladderThe cosmic distance ladder is the succession of methods by which astronomers determine the distances to celestial objects. A real direct distance measurement of an astronomical object is possible only for those objects that are "close enough" to Earth...
– - Hubble constant –
- Olber's paradox –
- UniverseUniverseThe Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
–
North Africa
Algerian Space Agency National Authority for Remote Sensing and Space Sciences- Egypt Remote Sensing Center Royal Centre for Remote Sensing National Remote Sensing Center
Sub-Saharan
National Space Research and Development AgencyNational Space Research and Development Agency
The National Space Research and Development Agency is the national space agency of Nigeria. It is a part of the Federal Ministry of Science and Technology and it is overseen by the National Council on Space Science Technology.-History:...
South African National Space Agency
South African National Space Agency
The South African National Space Agency is South Africa's government agency responsible for the promotion and development of aeronautics and aerospace space research...
North America
Canadian Space Agency Agencia Espacial MexicanaAgencia Espacial Mexicana
The Mexican Space Agency is a space agency, approved by the Mexican Chamber of Deputies on April 20, 2010 after receiving a significant vote of confidence on April 26, 2006...
United States Department of Defense
United States Department of Defense
The United States Department of Defense is the U.S...
(Air Force Space Command
Air Force Space Command
Air Force Space Command is a major command of the United States Department of the Air Force, with its headquarters at Peterson Air Force Base, Colorado. AFSPC supports U.S. military operations worldwide through the use of many different types of satellite, launch and cyber operations....
- National Reconnaissance OfficeNational Reconnaissance OfficeThe National Reconnaissance Office , located in Chantilly, Virginia, is one of the 16 U.S. intelligence agencies. It designs, builds, and operates the spy satellites of the United States government.-Mission:...
- United States Army Space and Missile Defense CommandUnited States Army Space and Missile Defense CommandThe United States Army Space and Missile Defense Command is a specialized major command within the United States Army. The command was established in 1997...
- Transformational Communications Office
- United States Strategic CommandUnited States Strategic CommandUnited States Strategic Command is one of nine Unified Combatant Commands of the United States Department of Defense . The Command, including components, employs more than 2,700 people, representing all four services, including DoD civilians and contractors, who oversee the command's operationally...
) - NASANASAThe National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
South America
Comisión Nacional de Actividades EspacialesComisión Nacional de Actividades Espaciales
Comisión Nacional de Actividades Espaciales is the civilian agency of the government of Argentina in charge of the national space program.- History :...
Brazilian Space Agency
Brazilian Space Agency
The Brazilian Space Agency is the civilian authority in Brazil responsible for the country's burgeoning space program. It operates a spaceport at Alcântara and a rocket launch site at Barreira do Inferno...
- Brazilian General Command for Aerospace Technology
- National Institute for Space ResearchNational Institute for Space ResearchThe National Institute for Space Research is a research unit of the Brazilian Ministry of Science and Technology, whose main goals are fostering scientific research and technological applications and qualifying personnel in the fields of space and atmospheric sciences, space engineering, and space...
- Instituto Tecnológico de Aeronáutica Agencia Chilena del Espacio Colombian Space CommissionColombian Space CommissionThe Colombian Space Commission is Colombia’s government body for the promotion and use of space. It is in charge of promoting the development of space technology and communication satellites as well as applications for the navigation and maritime transportation in Colombia. It also works in the...
Ecuadorian Civilian Space AgencyEcuadorian Civilian Space AgencyThe Ecuadorian Civilian Space Agency is the organization in charge of administering and executing the Ecuadorian civilian space program and conducting scientific research on space and planetary sciences. It is a mixed capital non-profit organization, 50% civilian and 50% Ecuadorian government...
National Commission for Aerospace Research & Development Aeronautics & Space Research and Diffusion Center Agencia Bolivariana para Actividades EspacialesAgencia Bolivariana para Actividades EspacialesThe Agencia Bolivariana para Actividades Espaciales is an organisation belonging to Venezuela's Ministry of the Popular Power for Science and Technology. Its mission is to develop and carry out the policies of Venezuela's Executive Power regarding the peaceful uses of outer space... - Instituto Venezolano de Investigaciones Científicas
East Asia
China Aerospace Science and Technology CorporationChina Aerospace Science and Technology Corporation
The China Aerospace Science and Technology Corporation is the main contractor for the Chinese space program. It is state-owned and has a number of subordinate entities which design, develop and manufacture a range of spacecraft, launch vehicles, strategic and tactical missile systems, and ground...
(China Academy of Launch Vehicle Technology
China Academy of Launch Vehicle Technology
The China Academy of Launch Vehicle Technology is the premier space launch vehicle manufacturer in China and one of the major launch service providers in the world. CALT is a subordinate of the larger China Aerospace Science and Technology Corporation...
- China Academy of Space TechnologyChina Academy of Space TechnologyThe China Academy of Space Technology is an organizational unit of China Aerospace Science and Technology Corporation .CAST designs and manufactures Dong Fang Hong satellites.- External links :...
- China Chang FengChina Chang FengChina Changfeng Mechanics and Electronics Technology Academy or China Changfeng, founded in 1957, is one of the four design academies under the China Aerospace Science and Technology Corporation...
- China Aerospace Science and Technology CorporationChina Aerospace Science and Technology CorporationThe China Aerospace Science and Technology Corporation is the main contractor for the Chinese space program. It is state-owned and has a number of subordinate entities which design, develop and manufacture a range of spacecraft, launch vehicles, strategic and tactical missile systems, and ground...
- Commission for Science, Technology and Industry for National Defense)
- China National Space AdministrationChina National Space AdministrationThe China National Space Administration is the national space agency of the People's Republic of China responsible for the national space program. It is responsible for planning and development of space activities...
Japan Aerospace Exploration AgencyJapan Aerospace Exploration AgencyThe , or JAXA, is Japan's national aerospace agency. Through the merger of three previously independent organizations, JAXA was formed on October 1, 2003, as an Independent Administrative Institution administered by the Ministry of Education, Culture, Sports, Science and Technology and the...
(Institute of Space and Astronautical ScienceInstitute of Space and Astronautical Scienceis a Japanese national research organization of astrophysics using rockets, astronomical satellites and interplanetary probes. It is a division of Japan Aerospace Exploration Agency .- History :... - National Aerospace Laboratory of Japan
- National Space Development Agency of JapanNational Space Development Agency of Japanof Japan, or NASDA, was a Japanese national space agency established on October 1, 1969 under the National Space Development Agency Law only for peaceful purposes...
) - National Institute of Information and Communications TechnologyNational Institute of Information and Communications TechnologyThe National Institute of Information and Communications Technology is Japan's national research institute for information and communications...
- Institute for Unmanned Space Experiment Free FlyerInstitute for Unmanned Space Experiment Free FlyerThe is a Japanese space agency, which was founded by the Ministry of International Trade and Industry in 1986. Unlike NASDA, ISAS, and NAL, it was not included in the 2003 founded JAXA organization. USEF is run as a Non Profit Organization...
National Remote Sensing Center Korean Committee of Space TechnologyKorean Committee of Space TechnologyThe Korean Committee of Space Technology is the state-controlled space agency of North Korea. Very little information on it is publicly available. It is known to be founded sometime in the 1980s, and most likely is connected to the Artillery Guidance Bureau of the Korean People's Army...
Korea Aerospace Research InstituteKorea Aerospace Research InstituteThe Korea Aerospace Research Institute is the aeronautics and space agency of South Korea. Its main laboratories are located in Daejeon, in the Daedeok Science Town. Current projects include the KSLV launcher. Past projects include the 1999 Arirang-1 satellite. The agency was founded in 1989...
National Space Organization
Southeast Asia
National Institute of Aeronautics and SpaceNational Institute of Aeronautics and Space
National Institute of Aeronautics and Space is the Indonesian government space agency. It was established on November 27, 1964 by former Indonesian president Suharto after one year's existence of an informal space agency organization. LAPAN is responsible for long-term civilian and military...
Malaysian National Space Agency Philippine Atmospheric, Geophysical and Astronomical Services Administration
Philippine Atmospheric, Geophysical and Astronomical Services Administration
The Philippine Atmospheric, Geophysical and Astronomical Services Administration is a Philippine national institution dedicated to provide flood and typhoon warnings, public weather forecasts and advisories, meteorological, astronomical, climatological, and other specialized information and...
Thai Ministry of Science and Technology's Space Agency Space Technology Institute
- Vietnam Space Commission
South Asia
Space Research and Remote Sensing OrganizationSpace Research and Remote Sensing Organization
Bangladesh Space Research and Remote Sensing Organization is the national space research and exploration agency of Bangladesh. Established in 1980 as an autonomous multisectoral R & D organization of the Bangladesh government, SPARRSO has been the national focal point for peaceful applications of...
Indian Space Research Organisation
Indian Space Research Organisation
The Indian Space Research Organisation is an independent Indian governmental agency established in 1969 for the research and development of vehicles and activities for the exploration of space within and outside of Earth’s atmosphere. Headquartered in Bangalore...
(Antrix Corporation
Antrix Corporation
Antrix Corporation Limited is commercial wing of Indian Space Research Organization . The name "Antrix" is an anglicized version of Antariksh, from the Sanskrit word for "space" or "sky".-Products and services:...
- Department of SpaceDepartment of SpaceThe Department of Space is an Indian government department responsible for administration of the Indian space program.The Indian Space Research Organization is the primary research and development arm of the DoS...
) Space and Upper Atmosphere Research CommissionSpace and Upper Atmosphere Research CommissionThe Space and Upper Atmosphere Research Commission , is an executive agency of the Government of Pakistan, responsible for nation's public and civil space program and aeronautics and aerospace research...
Sri Lanka Aeronautics and Space Agency
Southwest Asia
Azerbaijan National Aerospace AgencyAzerbaijan National Aerospace Agency
Azerbaijan National Aerospace Agency Azerbaijan National Aerospace Agency Azerbaijan National Aerospace Agency (ANASA; , is a governmental body that coordinates all Azerbaijani space research programs with scientific and commercial goals...
Iran Aviation Industries Organization
Iran Aviation Industries Organization
The Iran Aviation Industries Organization was established in 1966 for the purpose of planning, controlling, and managing the military aviation industry of Iran....
- Iranian Space AgencyIranian Space AgencyThe Iranian Space Agency is Iran's governmental space agency. Iran is an active participant in the Asian space race and became an orbital-launch-capable nation in 2009...
Israel Space Agency - National Committee for Space Research TÜBİTAK UZAYTUBITAK Space Technologies Research InstituteTÜBİTAK UZAY was founded in 1985, under the framework of a protocol signed between the Middle East Technical University and The Scientific and Technological Research Council of Turkey as a publicly funded research institute.TÜBİTAK UZAY specializes in space technologies, electronics, information...
Central Asia
KazCosmosKazCosmos
The National Space Agency of the Republic of Kazakhstan , also known as KazCosmos, or KazKosmos, is Kazakhstan's national space agency, and was officially established on March 27, 2007. The previous year, on June 18, 2006, the communications satellite KazSat 1 was launched from Baikonur Cosmodrome,...
- Kazakh Space Research Institute Turkmenistan National Space AgencyTurkmenistan National Space AgencyTurkmenistan National Space Agency , is a governmental body that coordinates all Turkmenistan space research programs with scientific and commercial goals. It was established in 2011.-Space Programme:...
UzbekCosmos
Europe
Austrian Space AgencyAustrian Space Agency
The Austrian Space Agency is an organization whose purpose is to coordinate Austrian space exploration-related activities, both national programs and European Space Agency related programs. It was established in 1972 in Vienna...
Belarus Space Agency Belgian Institute for Space Aeronomy
Belgian Institute for Space Aeronomy
The Belgian Institute for Space Aeronomy is a Belgian federal scientific research institute...
Bulgarian Space Agency Czech Space Office
Czech Space Office
The Czech Space Office, CSO is the central contact point for the coordination of pure space sciece related activities in the Czech Republic. It fulfils tasks of the national information and advisory centre for the academia on opportunities to enter the international space scene and on space...
Danish National Space Center
Danish National Space Center
The Danish National Space Center is a Danish sector research Institute and a part of the Danish Ministry of Science, Technology and Innovation. It is located in Copenhagen at Østerbro...
- esa European Cooperation for Space StandardizationEuropean Cooperation for Space StandardizationThe European Cooperation for Space Standardization , established in 1993, is an organization which works to improve standardization within the European space sector. The ECSS frequently publishes standards, to which contractors working for ESA must adhere to.-References:*- External links :* * at...
- European Space AgencyEuropean Space AgencyThe European Space Agency , established in 1975, is an intergovernmental organisation dedicated to the exploration of space, currently with 18 member states...
EUMETSAT - European Union Satellite CentreEuropean Union Satellite CentreThe European Union Satellite Centre is an agency of the European Union's Council of Ministers which gathers information through satellite images....
CNESCNESThe is the French government space agency . Established under President Charles de Gaulle in 1961, its headquarters are located in central Paris and it is under the supervision of the French Ministries of Defence and Research...
German Aerospace CenterGerman Aerospace CenterThe German Aerospace Center is the national centre for aerospace, energy and transportation research of the Federal Republic of Germany. It has multiple locations throughout Germany. Its headquarters are located in Cologne. It is engaged in a wide range of research and development projects in...
Institute for Space Applications and Remote SensingInstitute for Space Applications and Remote SensingThe Institute for Space Applications and Remote Sensing is a research institute in Greece with expertise in multidisciplinary space and environmental sciences, and one of the five research Institutes of the National Observatory of Athens...
Hungarian Space OfficeHungarian Space OfficeThe Hungarian Space Office is the national space agency of the Republic of Hungary. It was established by the Hungarian government in 1992. , the current director is Előd Both .-External links:* - English page...
Space Ireland Italian Space AgencyItalian Space AgencyThe Italian Space Agency is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy...
Space Science and Technology Institute LuxinnovationLuxinnovationLuxinnovation is the National Agency for Innovation and Research of Luxembourg. It offers a wide variety of services to Luxembourg-based bodies from both the private and the public sector as well as individuals...
Netherlands Institute for Space ResearchNetherlands Institute for Space ResearchSRON Netherlands Institute for Space Research is the Dutch expertise institute for space research. The Institute develops and uses innovative technology for groundbreaking research in space, focusing on astrophysical research, Earth science and planetary research...
Norwegian Space CentreNorwegian Space CentreThe Norwegian Space Centre is a Norwegian government agency that promotes space exploration.-Norsk Romsenter :...
Space Research CentreSpace Research CentreThe Space Research Centre is an interdisciplinary research institute of the Polish Academy of Sciences. It was established in 1977. SRC PAS is the only institute in Poland whose activity is fully dedicated to the research of terrestrial space, the solar system and the Earth using space technology...
Portuguese Space Company Romanian Space AgencyRomanian Space AgencyThe Romanian Space Agency is the Romanian national Coordinator for space-related technology, activities and programs since 1991....
Russian Federal Space AgencyRussian Federal Space AgencyThe Russian Federal Space Agency , commonly called Roscosmos and abbreviated as FKA and RKA , is the government agency responsible for the Russian space science program and general aerospace research. It was previously the Russian Aviation and Space Agency .Headquarters of Roscosmos are located... - Russian Space Research InstituteRussian Space Research InstituteThe Russian Space Research Institute is the leading organization of the Russian Academy of Sciences on space exploration to benefit fundamental science....
- Russian Space Forces Soviet space programSoviet space programThe Soviet space program is the rocketry and space exploration programs conducted by the former Union of Soviet Socialist Republics from the 1930s until its dissolution in 1991...
Instituto Nacional de Técnica AeroespacialInstituto Nacional de Técnica AeroespacialThe Instituto Nacional de Técnica Aeroespacial is Spain's space agency. It was founded in 1942, as the Instituto Nacional de Técnica Aeronáutica , and has its headquarters in Torrejón de Ardoz, near Madrid....
Swedish National Space BoardSwedish National Space BoardThe Swedish National Space Board is a Swedish government agency operating under the Swedish Ministry of Education and Science. SNSB distributes government grants to research and development, initiates research and development in space and remote sensing, and is the Swedish contact in international...
Swiss Space OfficeSwiss Space OfficeSwiss Space Office is the national space program of the Switzerland. It was roughly the 16th highest funded public space agency with a budget of about 110 million USD in the early 2000s. According to Jane's, the SSO is "the administrative unit charged with planning and implementing Swiss space...
UK Space AgencyUK Space AgencyThe UK Space Agency is a United Kingdom government agency responsible for its civil space programme. It was established on 1 April 2010 to replace the British National Space Centre and took over responsibility for government policy and key budgets for space and represents the UK in all negotiations...
State Space Agency of Ukraine
World
- Asia-Pacific Space Cooperation OrganizationAsia-Pacific Space Cooperation OrganizationThe Asia-Pacific Space Cooperation Organization is an inter-governmental organization operated as a non-profit independent body with full international legal status...
- Consultative Committee for Space Data SystemsConsultative Committee for Space Data SystemsThe Consultative Committee for Space Data Systems was formed in 1982 by the major space agencies of the world to provide a forum for discussion of common problems in the development and operation of space data systems...
- Committee on Space Research
- International Academy of AstronauticsInternational Academy of AstronauticsThe International Academy of Astronautics is an international community of experts committed to expanding the frontiers of space. It is a non-governmental organisation established in Stockholm on August 16, 1960....
- International Telecommunications Satellite OrganizationInternational Telecommunications Satellite OrganizationThe International Telecommunications Satellite Organization is an intergovernmental organisation charged with overseeing the public service obligations of Intelsat.-External links:*...
- IntercosmosIntercosmosInterkosmos was a space program of the Soviet Union designed to include members of military forces of allied Warsaw Pact countries in manned and unmanned missions...
- IntersputnikIntersputnikThe Intersputnik International Organization of Space Communications commonly known as Intersputnik is an international satellite communications services organization founded on November 15, 1971, in Moscow by the Soviet Union along with a group of eight formerly socialist states...
Pan-Arab Space Agency United Nations Committee on the Peaceful Uses of Outer SpaceUnited Nations Committee on the Peaceful Uses of Outer SpaceThe United Nations Committee on the Peaceful Uses of Outer Space was established in 1958 as an ad hoc committee... - United Nations Office for Outer Space AffairsUnited Nations Office for Outer Space AffairsThe United Nations Office for Outer Space Affairs is an organization of the General Assembly charged with implementing the Assembly's outer space-related policies. It is located in the United Nations Office in Vienna. The Office implements the Program on Space Applications and maintains the...
- See also: Timeline of first orbital launches by country
Preceded by the Soviet space program
Soviet space program
The Soviet space program is the rocketry and space exploration programs conducted by the former Union of Soviet Socialist Republics from the 1930s until its dissolution in 1991...
Books and publications
- AlmagestAlmagestThe Almagest is a 2nd-century mathematical and astronomical treatise on the apparent motions of the stars and planetary paths. Written in Greek by Claudius Ptolemy, a Roman era scholar of Egypt,...
– - Astronomia NovaAstronomia novaThe Astronomia nova is a book, published in 1609, that contains the results of the astronomer Johannes Kepler's ten-year long investigation of the motion of Mars...
– - Astronomical JournalAstronomical JournalThe Astronomical Journal is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by Institute of Physics Publishing. It is one of the premier journals for astronomy in the world...
– - Astrophysical JournalAstrophysical JournalThe Astrophysical Journal is a peer-reviewed scientific journal covering astronomy and astrophysics. It was founded in 1895 by the American astronomers George Ellery Hale and James Edward Keeler. It publishes three 500-page issues per month....
– - BD CatalogueDurchmusterungIn astronomy, Durchmusterung or Bonner Durchmusterung , is the usual name for three comprehensive astrometric star catalogues of the whole sky, processed by the Bonn Observatory from 1859 to 1903....
– - De Revolutionibus –
- Henry Draper CatalogueHenry Draper CatalogueThe Henry Draper Catalogue is an astronomical star catalogue published between 1918 and 1924, giving spectroscopic classifications for 225,300 stars; it was later expanded by the Henry Draper Extension , published between 1925 and 1936, which gave classifications for 46,850 more stars, and by the...
– - Isaac Asimov's Guide to Earth and SpaceIsaac Asimov's Guide to Earth and SpaceGuide to Earth and Space is a non-fiction work by the well-known science fiction writer Isaac Asimov. The book differs somewhat in structure from typical literature by presenting its information in the form of answers to a series of questions, presumably posed by the reader...
– - Messier Catalogue –
- New General CatalogueNew General CatalogueThe New General Catalogue of Nebulae and Clusters of Stars is a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects...
– - PrincipiaPrincipiaPrincipia could refer to:*Philosophiae Naturalis Principia Mathematica, Isaac Newton's three-volume work containing explanations of his laws of motion and his law of universal gravitation*Principia , a stem-group coralline alga...
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Astronomers
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- Walter BaadeWalter BaadeWilhelm Heinrich Walter Baade was a German astronomer who worked in the USA from 1931 to 1959.-Biography:He took advantage of wartime blackout conditions during World War II, which reduced light pollution at Mount Wilson Observatory, to resolve stars in the center of the Andromeda galaxy for the...
– - Friedrich BesselFriedrich Bessel-References:* John Frederick William Herschel, A brief notice of the life, researches, and discoveries of Friedrich Wilhelm Bessel, London: Barclay, 1847 -External links:...
– - Tycho BraheTycho BraheTycho Brahe , born Tyge Ottesen Brahe, was a Danish nobleman known for his accurate and comprehensive astronomical and planetary observations...
– - Annie Jump CannonAnnie Jump CannonAnnie Jump Cannon was an American astronomer whose cataloging work was instrumental in the development of contemporary stellar classification. With Edward C...
– - Alvan ClarkAlvan ClarkAlvan Clark , born in Ashfield, Massachusetts, the descendant of a Cape Cod whaling family of English ancestry, was an American astronomer and telescope maker. He was a portrait painter and engraver , and at the age of 40 became involved in telescope making...
– - Nicholas Copernicus –
- Galileo –
- George Ellery HaleGeorge Ellery HaleGeorge Ellery Hale was an American solar astronomer.-Biography:Hale was born in Chicago, Illinois. He was educated at MIT, at the Observatory of Harvard College, , and at Berlin . As an undergraduate at MIT, he is known for inventing the spectroheliograph, with which he made his discovery of...
– - William HerschelWilliam HerschelSir Frederick William Herschel, KH, FRS, German: Friedrich Wilhelm Herschel was a German-born British astronomer, technical expert, and composer. Born in Hanover, Wilhelm first followed his father into the Military Band of Hanover, but emigrated to Britain at age 19...
– - Edwin HubbleEdwin HubbleEdwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...
| Jacobus KapteynJacobus KapteynJacobus Cornelius Kapteyn, was a Dutch astronomer, best known for his extensive studies of the Milky Way and as the first discoverer of evidence for galactic rotation....
– - Johannes KeplerJohannes KeplerJohannes Kepler was a German mathematician, astronomer and astrologer. A key figure in the 17th century scientific revolution, he is best known for his eponymous laws of planetary motion, codified by later astronomers, based on his works Astronomia nova, Harmonices Mundi, and Epitome of Copernican...
– - Gerard KuiperGerard KuiperGerard Peter Kuiper , Netherlands – December 24, 1973, Mexico City) was a Dutch-American astronomer after whom the Kuiper belt was named.-Early life:...
– - Henrietta Leavitt –
- Isaac NewtonIsaac NewtonSir Isaac Newton PRS was an English physicist, mathematician, astronomer, natural philosopher, alchemist, and theologian, who has been "considered by many to be the greatest and most influential scientist who ever lived."...
– - Edward C. Pickering –
- PtolemyPtolemyClaudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
– - Henry Norris RussellHenry Norris RussellHenry Norris Russell was an American astronomer who, along with Ejnar Hertzsprung, developed the Hertzsprung–Russell diagram . In 1923, working with Frederick Saunders, he developed Russell–Saunders coupling which is also known as LS coupling.-Biography:Russell was born in 1877 in Oyster Bay, New...
– - Harlow ShapleyHarlow ShapleyHarlow Shapley was an American astronomer.-Career:He was born on a farm in Nashville, Missouri, and dropped out of school with only the equivalent of a fifth-grade education...
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See also
- PlanetPlanetA planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
- Star clusterStar clusterStar clusters or star clouds are groups of stars. Two types of star clusters can be distinguished: globular clusters are tight groups of hundreds of thousands of very old stars which are gravitationally bound, while open clusters, more loosely clustered groups of stars, generally contain less than...
- Stellar association
- Open clusterOpen clusterAn open cluster is a group of up to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way Galaxy, and many more are thought to exist...
- Globular clusterGlobular clusterA globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
- GalaxyGalaxyA galaxy is a massive, gravitationally bound system that consists of stars and stellar remnants, an interstellar medium of gas and dust, and an important but poorly understood component tentatively dubbed dark matter. The word galaxy is derived from the Greek galaxias , literally "milky", a...
- SuperclusterSuperclusterSuperclusters are large groups of smaller galaxy groups and clusters and are among the largest known structures of the cosmos. They are so large that they are not gravitationally bound and, consequently, partake in the Hubble expansion.-Existence:...
- HelioseismologyHelioseismologyHelioseismology is the study of the propagation of wave oscillations, particularly acoustic pressure waves, in the Sun. Unlike seismic waves on Earth, solar waves have practically no shear component . Solar pressure waves are believed to be generated by the turbulence in the convection zone near...
- Guest starGuest star (astronomy)In Chinese astronomy, the term guest star refers to a star which has suddenly appeared visible in the place where no star had previously been observed and becomes invisible again after some time. The term is a literal translation from ancient Chinese astronomical records...
- ConstellationConstellationIn modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
- AsterismAsterism (astronomy)In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...
- GravitationGravitationGravitation, or gravity, is a natural phenomenon by which physical bodies attract with a force proportional to their mass. Gravitation is most familiar as the agent that gives weight to objects with mass and causes them to fall to the ground when dropped...
- Intergalactic starIntergalactic starAn intergalactic star is a star which does not belong to a galaxy. These stars were a source of much discussion in the scientific community during the late 1990s and are generally thought to be the result of colliding galaxies.-Discovery:...
- Infrared dark cloudInfrared dark cloudAn infrared dark cloud is a cold, dense region of a giant molecular cloud). They can be seen in silhouette against the bright diffuse mid-infrared emission from Galactic plane.-Discovery:...
External links
- Astronomy Guide For reviews on astronomy products, how-to's and current events.
- Astronomy Net Resources, forums (from 1995), articles on Astronomy.
- International Year of Astronomy 2009 IYA2009 Main website
- Cosmic Journey: A History of Scientific Cosmology from the American Institute of Physics
- Astronomy Picture of the Day
- Southern Hemisphere Astronomy
- Sky & Telescope publishers
- Astronomy Magazine
- Latest astronomy news in 11 languages
- Universe Today for astronomy and space-related news
- Celestia Motherlode Educational site for Astronomical journeys through space
- Search Engine for Astronomy
- Hubblesite.org - home of NASA's Hubble Space Telescope
- Astronomy - A History - G. Forbes - 1909 (eLibrary Project - eLib Text)
- (historical)
- Prof. Sir Harry Kroto, NL, Astrophysical Chemistry Lecture Series. 8 Freeview Lectures provided by the Vega Science Trust.
- Core books and core journals in Astronomy, from the Smithsonian/NASA Astrophysics Data SystemAstrophysics Data SystemThe Astrophysics Data System , developed by the National Aeronautics and Space Administration , is an online database of over eight million astronomy and physics papers from both peer reviewed and non-peer reviewed sources...