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Deneb (a Cyg / a Cygni / Alpha
Alpha (letter)

Alpha is the first letter of the Greek alphabet. In the system of Greek numerals it has a value of 1. It was derived from the Phoenician alphabet Aleph ....
 Cygni) is the brightest star
Star

A star is a massive, luminous ball of Plasma that is held together by its own gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth....
 in the constellation
Constellation

A constellation is a group of stars that appear to have a physical proximity in the sky. The stars in a constellation are often vastly distant from each other, but they appear close to each other from the perspective of Earth....
 Cygnus
Cygnus (constellation)

Cygnus is a northern constellation. Its name is Latin for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross ....
 and one of the vertices of the Summer Triangle
Summer Triangle

The Summer Triangle is an astronomical asterism involving an imaginary triangle drawn on the northern hemisphere's celestial sphere, with its defining vertices at Altair, Deneb, and Vega....
. It is the 19th brightest star in the night sky
List of brightest stars

Bright stars are bright because they have high luminosity and/or they are nearby. Below are the 91 brightest individual stars as seen from Earth in visible wavelengths ....
, with an apparent magnitude
Apparent magnitude

The apparent magnitude of a celestial body is a measurement of its brightness as seen by an observer on Earth, normalized to the value it would have in the absence of the Earth's atmosphere....
 of 1.25. A white supergiant, Deneb is also one of the most luminous stars
List of most luminous stars

Below is a list of stars arranged in order of increasing absolute bolometric magnitude . Absolute magnitude is the apparent magnitude a star would have if it were 10 parsecs away from us....
 known. It is, or has been, known by a number of other traditional names, including Arided and Aridif, but today these are almost entirely forgotten.

Distance and physical characteristics
Deneb's absolute magnitude
Absolute magnitude

In astronomy, absolute magnitude measures a celestial object's intrinsic brightness. To derive the absolute magnitude from the observed apparent magnitude of a celestial object its value is corrected for distance to the observer....
 is about −7, placing it among the most luminous stars known.

Deneb's exact distance from the Earth is uncertain, which makes determining many of Deneb's other properties similarly imprecise.






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Deneb (a Cyg / a Cygni / Alpha
Alpha (letter)

Alpha is the first letter of the Greek alphabet. In the system of Greek numerals it has a value of 1. It was derived from the Phoenician alphabet Aleph ....
 Cygni) is the brightest star
Star

A star is a massive, luminous ball of Plasma that is held together by its own gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth....
 in the constellation
Constellation

A constellation is a group of stars that appear to have a physical proximity in the sky. The stars in a constellation are often vastly distant from each other, but they appear close to each other from the perspective of Earth....
 Cygnus
Cygnus (constellation)

Cygnus is a northern constellation. Its name is Latin for swan. One of the most recognizable constellations of the northern summer and autumn, it features a prominent asterism known as the Northern Cross ....
 and one of the vertices of the Summer Triangle
Summer Triangle

The Summer Triangle is an astronomical asterism involving an imaginary triangle drawn on the northern hemisphere's celestial sphere, with its defining vertices at Altair, Deneb, and Vega....
. It is the 19th brightest star in the night sky
List of brightest stars

Bright stars are bright because they have high luminosity and/or they are nearby. Below are the 91 brightest individual stars as seen from Earth in visible wavelengths ....
, with an apparent magnitude
Apparent magnitude

The apparent magnitude of a celestial body is a measurement of its brightness as seen by an observer on Earth, normalized to the value it would have in the absence of the Earth's atmosphere....
 of 1.25. A white supergiant, Deneb is also one of the most luminous stars
List of most luminous stars

Below is a list of stars arranged in order of increasing absolute bolometric magnitude . Absolute magnitude is the apparent magnitude a star would have if it were 10 parsecs away from us....
 known. It is, or has been, known by a number of other traditional names, including Arided and Aridif, but today these are almost entirely forgotten.

Distance and physical characteristics


Deneb's absolute magnitude
Absolute magnitude

In astronomy, absolute magnitude measures a celestial object's intrinsic brightness. To derive the absolute magnitude from the observed apparent magnitude of a celestial object its value is corrected for distance to the observer....
 is about −7, placing it among the most luminous stars known.

Deneb's exact distance from the Earth is uncertain, which makes determining many of Deneb's other properties similarly imprecise. However, the uncertainty has been dramatically reduced upon analysis of the New Hipparcos
Hipparcos

Hipparcos was a scientific mission of the European Space Agency , launched in 1989 and operated between 1989 and 1993. It was the first space experiment devoted to astrometry, the accurate measurement of star positions, parallaxes, and proper motions....
 Data Reduction in 2007. One 2008 study puts the most likely distance at approximately 1,550 light-years, and the reduced parallax
Parallax

Parallax is an apparent displacement or difference of orientation of an object viewed along two different lines of sight, and is measured by the angle or semi-angle of inclination between those two lines....
 uncertainties do not rule out a distance as close as 1,340 light-years or as far as 1,840 light-years

Deneb is a blue-white colored star and it's the farthest first-magnitude star from Earth.

Deneb's estimated luminosity is 60,000 times the brightness of our Sun
Sun

The Sun , a G V star, is the star at the center of the Solar System. The Earth and other matter orbit the Sun, which by itself accounts for about 98.6% of the Solar System's mass....
.

Based on its temperature and luminosity and also on direct measurements of its tiny angular diameter
Angular diameter

The angular diameter of an object as seen from a given position is the "visual diameter" of the object measured as an angle. In the vision sciences it is called the visual angle....
 (a mere 0.002 second of arc), Deneb appears to have a diameter about 200 times that of the Sun; if placed at the center of our Solar System, Deneb would extend to the orbit of the Earth. It is one of the largest stars known
List of largest known stars

Below is a list of the largest known stars by radius . A unit of measurement is the Solar radius .The exact order of this list is not complete yet, nor is it completely well defined:...
 and the most powerful class A star identified.

A star of spectral type
Stellar classification

In astronomy, stellar classification is a classification of stars based on its spectrum characteristics. The spectral class of a star, is a designation of a class to a star describing the ionization of its chromosphere, what atomic excited states are most prominent in the light, giving an objective measure of the temperature in this chr...
 A2Ia, Deneb has a surface temperature of 8,400 kelvins. Deneb is the prototype of a class of variable star
Variable 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....
s known as Alpha Cygni variable
Alpha Cygni variable

Alpha Cygni variables are Variable star which exhibit non-radial pulsations. They are supergiant stars of Stellar classification B or A. Variations in brightness on the order of 0.1 apparent magnitude are associated with the radial pulsations, which often seem irregular variable, due to Beat ing of multiple pulsation periods....
s. Its surface undergoes non-radial fluctuations, which cause its brightness and spectral type to change slightly.

Deneb's mass is estimated at 20 to 25 solar masses. As a white supergiant
Supergiant

Supergiants are among the most massive stars. In the Hertzsprung-Russell diagram they occupy the top region of the diagram. In the spectral classification supergiants are class Ia or Ib ....
, its high mass and temperature mean that the star will have a short lifespan and will probably become a supernova
Supernova

A supernova is a Astronomy#Stellar astronomy explosion. 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....
 within a few million years. It has already stopped fusing hydrogen
Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....
 in its core.

Deneb's solar wind
Solar wind

The solar wind is a Electric current—a Plasma —ejected from the stellar atmosphere of the sun. It consists mostly of electrons and protons with energies of about 1 electron volt....
 causes it to lose mass at a rate of 0.8 millionth of a solar mass per year, a hundred thousand times the flow rate from the Sun.

Etymology and cultural significance


The name Deneb is derived from dhaneb, the Arabic for "tail", from the phrase ??? ??????? Dhanab ad-Dajajah, or "tail of the hen". Similar names were given to at least seven different stars, most notably Deneb Kaitos, the brightest star in the constellation Cetus
Cetus

Cetus is a constellation in the northern sky. Its name refers to Cetus , a sea monster in Greek mythology, although it is often called 'the whale' today....
, and Denebola
Denebola

Denebola is the second brightest star in the constellation Leo . It is an A-class star that is about distant from earth, and has a luminosity about twelve times that of the sun....
, the second brightest star in Leo
Leo (constellation)

Leo is one of the constellations of the zodiac. Its name is Latin for lion. Its symbol is , a corruption of the initial letter of ?e?? . Leo lies between dim Cancer to the west and Virgo to the east....
.

Less contracted names include Deneb Adige, Denebadigege, and Denebedigege. Arided was used in the Alfonsine Tables
Alfonsine tables

The Alfonsine tables were ephemeris drawn up at Toledo, Spain by order of Alfonso X around 1252 to 1270 to correct anomalies in the Tables of Toledo....
, this latter name derived from Al Ridhadh, a name for the constellation. Johann Bayer
Johann Bayer

Johann Bayer was a Germany lawyer and Star cartographyer . He was born in Rain, Bavaria in 1572. He began his study of philosophy in Ingolstadt in 1592, and moved later to Augsburg to begin work as a lawyer....
 called it Arrioph, derived from Aridf and Al Ridf, 'the hindmost' or Gallina. Caesius
Caesius

Caesius may refer to:*Caesius Bassus, a Roman lyric poet*Caesius Nasica, a Roman military officer...
 termed it Os rosae, or Rosemund in German, or Uropygium – the parson's nose.

It is known as ??? (the Fourth Star of the Celestial Ford) in Chinese. In the Chinese love story of Qi Xi
Qi Xi

Qi Xi , also known as Magpie Festival, falls on the seventh day of the seventh lunar month on the Chinese calendar; thus its name. It also inspired Tanabata in Japan, Chilseok in Korea, and That Tich in Vietnam....
, Deneb marks the magpie
Magpie

Magpies are passerine birds of the crow family , Corvidae. The names 'jay' and 'magpie' are to a certain extent interchangeable, although this does not accurately reflect the evolutionary relationship between these birds....
 bridge across the Milky Way
Milky Way

The Milky Way, sometimes called simply the Galaxy, is the galaxy in which the Solar System is located. It is a barred spiral galaxy that is part of the Local Group of galaxies....
 which allows the separated lovers Niu Lang (Altair
Altair

Altair is the brightest star in the constellation Aquila and the list of brightest stars in the night sky. It is an Stellar classification#Class A main sequence star with an apparent visual magnitude of 0.77 and is one of the vertices of the Summer Triangle; the other two are Deneb and Vega....
) and Zhi Nü (Vega
Vega

Vega is the brightest star in the constellation Lyra, the list of brightest stars in the night sky and the second brightest star in the northern Celestial sphere, after Arcturus....
) to be reunited on one special night of the year in late summer. In other versions of the story Deneb is a fairy who acts as chaperone when the lovers meet across the bridge of magpies.

See also

  • Deneb in fiction
    Deneb in fiction

    Deneb , a highly luminous white supergiant star, is the brightest star in the constellation Cygnus and one of the List of brightest stars stars in the night sky....