Kepler Mission

Kepler Mission

Overview
The Kepler spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 is an American space observatory
Space observatory
A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects...

, the space-based portion of NASA
NASA
The 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...

's Kepler Mission to discover Earth-like planets
Terrestrial planet
A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun...

 orbiting other stars. The spacecraft is named in honor of the 17th-century German astronomer Johannes Kepler
Johannes Kepler
Johannes 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...

. The spacecraft was launched on March 7, 2009, with a planned mission lifetime of at least 3.5 years.

The Kepler mission is "specifically designed to survey a portion of our region of the Milky Way galaxy to discover dozens of Earth-size planets in or near the habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

 and determine how many of the billions of stars in our galaxy have such planets." Kepler's only instrument is a photometer
Photometer
In its widest sense, a photometer is an instrument for measuring light intensity or optical properties of solutions or surfaces. Photometers are used to measure:*Illuminance*Irradiance*Light absorption*Scattering of light*Reflection of light*Fluorescence...

 that continuously monitors the brightness of over 145,000 main sequence stars in a fixed field of view.
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Encyclopedia
The Kepler spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....

 is an American space observatory
Space observatory
A space observatory is any instrument in outer space which is used for observation of distant planets, galaxies, and other outer space objects...

, the space-based portion of NASA
NASA
The 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...

's Kepler Mission to discover Earth-like planets
Terrestrial planet
A terrestrial planet, telluric planet or rocky planet is a planet that is composed primarily of silicate rocks or metals. Within the Solar System, the terrestrial planets are the inner planets closest to the Sun...

 orbiting other stars. The spacecraft is named in honor of the 17th-century German astronomer Johannes Kepler
Johannes Kepler
Johannes 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...

. The spacecraft was launched on March 7, 2009, with a planned mission lifetime of at least 3.5 years.

The Kepler mission is "specifically designed to survey a portion of our region of the Milky Way galaxy to discover dozens of Earth-size planets in or near the habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

 and determine how many of the billions of stars in our galaxy have such planets." Kepler's only instrument is a photometer
Photometer
In its widest sense, a photometer is an instrument for measuring light intensity or optical properties of solutions or surfaces. Photometers are used to measure:*Illuminance*Irradiance*Light absorption*Scattering of light*Reflection of light*Fluorescence...

 that continuously monitors the brightness of over 145,000 main sequence stars in a fixed field of view. This data is analyzed to detect periodic fluctuations that indicate the presence of extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

s that are in the process of crossing the face
Astronomical transit
The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...

 of other stars.

Kepler is a project under NASA's Discovery Program
Discovery Program
NASA's Discovery Program is a series of lower-cost, highly-focused American scientific space missions that are exploring the Solar System. It was founded in 1992 to implement then-NASA Administrator Daniel S. Goldin's vision of "faster, better, cheaper" planetary missions...

 of relatively low-cost, focused science missions. The Ames Research Center is the home organization of the science principal investigator and is responsible for the ground system development, mission operations and science data analysis. The development of the Kepler mission was managed by NASA's Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 until December 2009, but was then transferred to the Ames Research Center. Ball Aerospace & Technologies Corp. was responsible for developing the Kepler flight system.

The Kepler observatory is currently in active operation, with the first main results announced on 4 January 2010. As expected, the initial discoveries were all short-period planets, with longer period planets expected later. The first six weeks of data revealed five previously unknown planets, all very close to their stars. Among the notable results are one of the least dense planets yet found, two low-mass white dwarf
White dwarf
A 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...

 stars that were initially reported as being members of a new class of stellar objects, and a well-characterized planet orbiting a binary star
Kepler-16b
Kepler-16b is an extrasolar planet. It is a Saturn-mass planet consisting of half rock and half gas, and it orbits a binary star, Kepler-16, with a period of 229 days...

.

On 2 February 2011, the Kepler team announced the results from the data of May to September 2009. They found 1,235 planetary candidates circling 997 host stars, more than twice the number of currently known exoplanets. The Kepler results included 68 planetary candidates of Earth-like size and 54 planetary candidates in the habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

 of their star, with 5 exoplanets falling in both categories. The team estimated that 5.4% of all stars host Earth-size planet candidates and 17% of all stars have multiple planets. As the mission continued, additional longer-period candidates were found – as of September 2011, there are a total of 1,781 candidates.

As of November 2011, the Kepler mission has released data from the first three "quarters" of its operation (roughly three months each, excluding the first quarter which is approximately one month). Additionally, the data used to support each discovery has become public following the formal publication of papers announcing the discovery.

The Kepler team originally promised to release data within one year of observations. However, this plan was changed after launch, with data being scheduled for release up to three years after its collection. This resulted in considerable criticism, leading the Kepler science team to release the second and third quarters of their data one year and nine months after collection. At the Extreme Solar Systems II meeting, Kepler Deputy PI Dr. Natalie Batalha announced that the fourth quarter of data (collected between December 2009 and March 2010) would be made publicly available in December 2011, and the data through June 2010 would be made public in January 2012.

Kepler spacecraft


The spacecraft has a mass of 1039 kilograms (2,290.6 lb), has a 0.95 metres (37.4 in) aperture
Aperture
In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. The aperture determines how collimated the admitted rays are,...

, and a 1.4 metres (55 in) primary mirror
Primary mirror
A primary mirror is the principal light-gathering surface of a reflecting telescope.-Description:The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal , or in later telescopes, glass or other material coated with a reflective layer...

 – at the time of its launch, this was the largest mirror on any telescope outside of Earth orbit. The spacecraft has a 115 deg2 (about 12 degree diameter) field of view
Field of view
The field of view is the extent of the observable world that is seen at any given moment....

 (FOV), roughly equivalent to the size of one's fist held at arm's length. Of this, 105 deg2 is of science quality, with less than 11% vignetting
Vignetting
In photography and optics, vignetting  is a reduction of an image's brightness or saturation at the periphery compared to the image center. The word vignette, from the same root as vine, originally referred to a decorative border in a book. Later, the word came to be used for a photographic...

. The photometer has a soft focus
Soft focus
In photography, soft focus is a lens flaw, in which the lens forms images that are blurred due to spherical aberration. A soft focus lens deliberately introduces spherical aberration in order to give the appearance of blurring the image while retaining sharp edges; it is not the same as an...

 to provide excellent photometry
Photometry (astronomy)
Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical object's electromagnetic radiation...

, rather than sharp images. The mission goal is a combined differential photometric precision (CDPP) of 20 ppm for a m(V)=12 solar-like star for a 6.5 hour integration, though the observations so far fall short of this objective (see mission status). An Earth-like transit produces a brightness change of 84 ppm and lasts for 13 hours when it crosses the center of the star.

Camera


The focal plane of the spacecraft's camera is made up of 42 CCDs
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

 at 2200 × 1024 pixels which makes it the largest camera launched into space with a resolution of 95 megapixels. The array is cooled by heat pipes connected to an external radiator. The CCDs are read out every six seconds (to limit saturation) and co-added on board for 30 minutes. However, even though at launch Kepler had the highest data rate of any NASA mission, the 30 minute sums of all 95 million pixels constitute more data than can be stored and sent back to Earth. Therefore the science team has pre-selected the relevant pixels associated with each star of interest, amounting to about 5 percent of the pixels. The data from these pixels is then requantized, compressed and stored, along with other auxiliary data, in the on-board 16 gigabyte solid-state recorder. Data that is stored and downlinked includes science stars, p-mode stars, smear, black level, background and full field-of-view images.

The mission's life-cycle cost is estimated at US$600 million, including funding for 3.5 years of operation.

Spacecraft history



In January 2006, the project was delayed eight months because of budget cuts and consolidation at NASA. It was delayed again by four months in March 2006 due to fiscal problems. At this time the high-gain antenna
High-gain antenna
A high-gain antenna is an antenna with a focused, narrow radiowave beam width. This narrow beam width allows more precise targeting of the radio signal - also known as a directional antenna...

 was changed from a gimbal
Gimbal
A gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain immobile regardless of the motion of its support...

led design to one fixed to the frame of the spacecraft to reduce cost and complexity, at the cost of one observation day per month.

The observatory was launched on March 7, 2009 at 03:49:57 UTC (March 6, 10:49:57 p.m. EST) aboard a Delta II rocket from Cape Canaveral Air Force Station
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...

, Florida. The launch was a complete success and all three stages were completed by 04:55 UTC. The cover of the telescope was jettisoned on April 7, 2009 and the first light images were taken on the next day.

On April 20, 2009, it was announced that the Kepler science team had concluded that further refinement of the focus would dramatically increase the scientific return. On April 23, 2009 it was announced that the focus had been successfully optimized by moving the primary mirror 40 micrometers (1.6 thousandths of an inch) towards the focal plane and tilting the primary mirror 0.0072 degree.

On May 12, 2009 at 5:01 p.m. Pacific Time
Pacific Time Zone
The Pacific Time Zone observes standard time by subtracting eight hours from Coordinated Universal Time . The clock time in this zone is based on the mean solar time of the 120th meridian west of the Greenwich Observatory. During daylight saving time, its time offset is UTC-7.In the United States...

 (17:01 UTC-8
UTC-8
UTC−08:00 is an identifier for a time offset from UTC of −08. This time is used in:-As standard time :*Canada**Northwest Territories***Tungsten and the associated Cantung Mine*Mexico...

), Kepler successfully completed its commissioning phase and began its search for planets around other stars.

On June 19, 2009, the spacecraft successfully sent its first science data to Earth. It was discovered that
Kepler had entered safe mode
Safe mode (spacecraft)
Safe mode is an operating mode of a modern spacecraft during which all non-essential systems are shut down and only essential functions such as thermal management, radio reception and attitude control are active.-Triggering events:...

 on June 15. A second safe mode event occurred on July 2. In both cases the event was triggered by a
processor reset. The spacecraft resumed normal operation on July 3 and the science data that had been collected since June 19 was downlinked that day. On October 14, 2009, the cause of these safing events was determined to be a low voltage power supply which provides power to the RAD750
RAD750
The RAD750 is a radiation-hardened single board computer, based on IBM's PowerPC 750. The successor of the RAD6000, the RAD750 is manufactured by BAE Systems Electronic Solutions. It is intended for use in high radiation environments such as experienced on board satellites and spacecraft...

 processor. On January 12, 2010, one portion of the focal plane transmitted anomalous data, suggesting a problem with focal plane MOD-3 module, covering 2 out of Keplers 42 CCDs
Charge-coupled device
A charge-coupled device is a device for the movement of electrical charge, usually from within the device to an area where the charge can be manipulated, for example conversion into a digital value. This is achieved by "shifting" the signals between stages within the device one at a time...

. As of October 2010, the module was described as "failed", but the coverage still exceeded the science goals.

Kepler downloads roughly 90-100 gigabit
Gigabit
The gigabit is a multiple of the unit bit for digital information or computer storage. The prefix giga is defined in the International System of Units as a multiplier of 109 , and therefore...

s of science data about once per month - an example of such a download was on 22–23 November 2010.

Once Kepler has detected a transit-like signature, it is necessary to rule out false positives with follow-up tests such as doppler spectroscopy
Doppler spectroscopy
Doppler spectroscopy, also known as radial velocity measurement, is a spectroscopic method for finding extrasolar planets. It involves the observation of Doppler shifts in the spectrum of the star around which the planet orbits....

. Although Kepler was designed for photometry it turns out that it is capable of astrometry
Astrometry
Astrometry 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...

 and such measurements can help confirm or rule out planet candidates.

Performance


In terms of photometric performance, Kepler is working well, much better than any Earth-bound telescope, but still short of the design goals. The objective was a combined differential photometric precision (CDPP) of 20 parts per million (PPM) on a magnitude 12 star for a 6.5 hour integration. This estimate was developed allowing 10 ppm for stellar variability, roughly the value for the Sun. The obtained accuracy for this observation has a wide range, depending on the star and position on the focal plane, with a median of 29 ppm. Most of the additional noise appears due to a larger-than-expected variability in the stars themselves (19.5 ppm as opposed to the assumed 10.0 ppm), with the rest due to instrumental noise sources slightly larger than predicted. Work to better understand, and perhaps calibrate out, instrument noise is ongoing.

Since the signal from an Earth size planet is so close to the noise level (only 80 ppm), the increased noise means each individual transit is only a 2.7 σ event, instead of the intended 4 σ. This, in turn, means more transits must be observed to be sure of a detection. Recent estimates indicate a 7-8 year mission, as opposed to the 3.5 year planned, would be needed to find all transiting Earth-sized planets. The spacecraft has enough fuel for such a mission, but there is no funding for it so far.

Spacecraft orbit and orientation




The Kepler space observatory is in a Heliocentric orbit
Heliocentric orbit
A heliocentric orbit is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet...

, so that Earth does not occlude the stars, which are observed continuously, and so the photometer
Photometer
In its widest sense, a photometer is an instrument for measuring light intensity or optical properties of solutions or surfaces. Photometers are used to measure:*Illuminance*Irradiance*Light absorption*Scattering of light*Reflection of light*Fluorescence...

 is not influenced by stray light from Earth. This orbit avoids the gravitational perturbations and torque
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....

s inherent in an Earth orbit, allowing for a more stable viewing platform. The photometer
Photometer
In its widest sense, a photometer is an instrument for measuring light intensity or optical properties of solutions or surfaces. Photometers are used to measure:*Illuminance*Irradiance*Light absorption*Scattering of light*Reflection of light*Fluorescence...

 points to a field in the northern constellation
Constellation
In 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....

s of Cygnus
Cygnus (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...

, Lyra and Draco
Draco (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...

, which is well out of the ecliptic
Ecliptic
The 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...

 plane, so that sunlight never enters the photometer as the spacecraft orbits the Sun. Cygnus is also a good choice to observe because it will never be obscured by Kuiper belt
Kuiper belt
The 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...

 objects or the asteroid belt
Asteroid belt
The 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...

.

An additional benefit of that choice is that Kepler is pointing in the direction of the Solar System's motion around the center of the galaxy. Thus, the stars which are observed by Kepler are roughly the same distance from the galactic center as the Solar System
Solar System
The 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...

, and also close to the galactic plane. This fact is important if position in the galaxy is related to habitability, as suggested by the Rare Earth hypothesis
Rare Earth hypothesis
In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the emergence of complex multicellular life on Earth required an improbable combination of astrophysical and geological events and circumstances...

.

Keplers orbit has been described by NASA as Earth-trailing. With an orbital period of 372.5 days, Kepler slowly falls further behind Earth.

Spacecraft operations



Kepler is operated out of Boulder, Colorado
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...

, USA, by the Laboratory for Atmospheric and Space Physics (LASP). The spacecraft's solar array will be rotated to face the Sun at the solstice
Solstice
A solstice is an astronomical event that happens twice each year when the Sun's apparent position in the sky, as viewed from Earth, reaches its northernmost or southernmost extremes...

s and equinox
Equinox
An equinox occurs twice a year, when the tilt of the Earth's axis is inclined neither away from nor towards the Sun, the center of the Sun being in the same plane as the Earth's equator...

es. These rotations will be used to optimize the amount of sunlight falling on the solar array and to keep the heat radiator pointing towards deep space. Together, LASP and Ball Aerospace & Technologies Corp. (who are responsible for building the spacecraft and instrument) control the spacecraft from the mission operations center located on the research campus of the University of Colorado
University of Colorado at Boulder
The University of Colorado Boulder is a public research university located in Boulder, Colorado...

. LASP performs essential mission planning and the initial collection and distribution of the science data.

Communications


NASA contacts the spacecraft using the X band
X band
The X band is a segment of the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of X band is rather indefinitely set at approximately 7.0 to 11.2 gigahertz . In radar engineering, the frequency range is specified...

 communication link twice a week for command and status updates. Scientific data are downloaded once a month using the Ka band
Ka band
The Ka band covers the frequencies of 26.5–40 GHz. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above" — in other words, the band directly above the K-band...

 link at a maximum data transfer rate of 4.33 Mbit/s. The Kepler spacecraft conducts its own partial analysis on board and only transmits scientific data deemed necessary to the mission in order to conserve bandwidth.

Data management


Science data telemetry collected during mission operations at LASP is sent on for processing at the Kepler Data Management Center (DMC), located at the Space Telescope Science Institute
Space Telescope Science Institute
The Space Telescope Science Institute is the science operations center for the Hubble Space Telescope and for the James Webb Space Telescope...

 on the campus of the Johns Hopkins University
Johns Hopkins University
The Johns Hopkins University, commonly referred to as Johns Hopkins, JHU, or simply Hopkins, is a private research university based in Baltimore, Maryland, United States...

 in Baltimore, Maryland. The science data telemetry is decoded and processed into uncalibrated FITS
FITS
Flexible Image Transport System is a digital file format used to store, transmit, and manipulate scientific and other images. FITS is the most commonly used digital file format in astronomy...

-format science data products by the DMC, which are then passed along to the Science Operations Center (SOC) at NASA Ames Research Center, for calibration and final processing. The SOC at NASA Ames Research Center (ARC) develops and operates the tools needed to process scientific data for use by the Kepler Science Office (SO). Accordingly, the SOC develops the pipeline data processing software based on scientific algorithms developed by the SO. During operations, the SOC (1) receives calibrated pixel data from the DMC, (2) applies the analysis algorithms to produce light curves for each star, (3) performs transit searches for detection of planets (threshold-crossing events, or TCEs) and (4) performs data validation of candidate planets by evaluating various data products for consistency as a way to eliminate false positive detections. The SOC also evaluates the photometric performance on an on-going basis and provides the performance metrics to the SO and Mission Management Office. Finally, the SOC develops and maintains the project’s scientific databases, including catalogs and processed data. The SOC finally returns calibrated data products and scientific results back to the DMC for long-term archiving, and distribution to astronomers around the world through the Multimission Archive at STScI (MAST).

Objectives and methods


The scientific objective of the Kepler mission is to explore the structure and diversity of planetary systems. This is achieved by surveying a large sample of stars to achieve several goals:
  • Determine how many Earth-size and larger planets there are in or near the habitable zone
    Habitable zone
    In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

     (often called "Goldilocks planets") of a wide variety of spectral types of stars.
  • Determine the range of size and shape of the orbits of these planets.
  • Estimate how many planets there are in multiple-star systems.
  • Determine the range of orbit size, brightness, size, mass and density of short-period giant planets.
  • Identify additional members of each discovered planetary system using other techniques.
  • Determine the properties of those stars that harbor planetary systems.


Most of the extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...

s detected so far by other projects are giant planets, mostly the size of Jupiter
Jupiter
Jupiter 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,...

 and bigger. Kepler is designed to look for planets 30 to 600 times less massive, closer to the order of Earth's mass (Jupiter is 318 times more massive than Earth). The method used, the transit method, involves observing repeated transit
Astronomical transit
The term transit or astronomical transit has three meanings in astronomy:* A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, hiding a small part of it, as seen by an observer at some particular vantage point...

 of planets in front of their stars, which causes a slight reduction in the star's apparent magnitude
Apparent magnitude
The 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...

, on the order of 0.01% for an Earth-size planet. The degree of this reduction in brightness can be used to deduce the diameter of the planet, and the interval between transits can be used to deduce the planet's orbital period, from which estimates of its orbital semi-major axis
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...

 (using Kepler's laws) and its temperature (using models of stellar radiation) can be calculated.

The probability
Probability
Probability is ordinarily used to describe an attitude of mind towards some proposition of whose truth we arenot certain. The proposition of interest is usually of the form "Will a specific event occur?" The attitude of mind is of the form "How certain are we that the event will occur?" The...

 of a random planetary orbit being along the line-of-sight to a star is the diameter of the star divided by the diameter of the orbit. For an Earth-like planet at 1 AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

 transiting a Sol-like star the probability is 0.465%, or about 1 in 215. At 0.72 AU (the orbital distance of Venus
Venus
Venus 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...

) the probability is slightly larger, at 0.65%; such planets could be Earth-like if the host star is a late G-type star
Stellar classification
In 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...

 such as Tau Ceti
Tau Ceti
Tau Ceti is a star in the constellation Cetus that is spectrally similar to the Sun, although it has only about 78% of the Sun's mass. At a distance of just under 12 light-years from the Solar System, it is a relatively close star. Tau Ceti is metal-deficient and so is thought to be less likely to...

. In addition, because planets in a given system tend to orbit in similar planes, the possibility of multiple detections around a single star is actually rather high. For instance, if a Kepler-like mission conducted by aliens observed Earth transiting the Sun, there is a 12% chance that it would also see Venus
Venus
Venus 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...

 transiting.

Kepler has a much higher probability of detecting Earth-like planets than the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...

, since it has a much larger field of view (approximately 10 degrees square), and is dedicated to detecting planetary transits. The Hubble Space Telescope, in contrast, is used to address a wide range of questions and rarely looks continuously at just one starfield. Of the approximately half-million stars in Keplers field of view, around 150,000 stars were selected for observation, and they are observed simultaneously, with the spacecraft measuring variations in their brightness every 30 minutes. This provides a better chance for seeing a transit. In addition, the 1-in-215 probability means that if 100% of stars observed had the same diameter as the Sun, and each had one Earth-like terrestrial planet in an orbit identical to that of the Earth, Kepler would find about 465; but if only 10% of stars observed were such, then it would find about 46. The mission is well suited to determine the frequency of Earth-like planets orbiting other stars.

Since
Kepler must see at least three transits to be sure the dimming was caused by a planet, and since larger planets give a signal that is easier to check, scientists expected the first reported results to be larger Jupiter-size planets in tight orbits. The first of these were reported after only a few months of operation. Smaller planets, and planets farther from their sun will take longer, and discovering planets comparable to Earth is expected to take three years or longer.

Data collected by Kepler is also being used for studying variable stars of various types and performing asteroseismology
Asteroseismology
Asteroseismology 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...

, particularly on stars showing solar-like oscillations
Solar-like oscillations
The 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...

.

Mission results to date





2009


NASA held a press conference to discuss early science results of the Kepler mission on August 6, 2009. At this press conference, it was revealed that
Kepler had confirmed the existence of the previously known transiting exoplanet HAT-P-7b
HAT-P-7b
HAT-P-7b is an extrasolar planet discovered in 2008. It orbits very close to its parent star GSC 03547-01402, and is both larger and more massive than Jupiter. Due to the extreme heat it receives from its star, the dayside temperature is predicted to be 2730 K...

, and was functioning well enough to discover Earth-size planets.

Since
Keplers detection of planets depends on seeing very small changes in brightness, stars that vary in brightness all by themselves (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) are not useful in this search. From the first few months of data, Kepler scientists have determined that about 7,500 stars from the initial target list are such variable stars. These were dropped from the target list, and will be replaced by new candidates. On November 4, 2009, the Kepler project publicly released the light curves of the dropped stars.

Ground-based follow-up studies of the first six weeks of data, revealed five previously unknown planets, all very close to their stars, one (Kepler-4b
Kepler-4b
Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's...

) slightly larger than Neptune and four (Kepler-5b
Kepler-5b
Kepler-5b is one of the first five planets discovered by NASA's Kepler spacecraft. It is a Hot Jupiter that orbits a subgiant star that is more massive, larger, and more diffuse than the Sun is...

, 6b
Kepler-6b
Kepler-6b is an extrasolar planet in the orbit of the unusually metal-rich Kepler-6, a star in the field of view of the NASA-operated Kepler spacecraft, which searches for planets that cross directly in front of, or transit, their host stars. It was the third planet to be discovered by Kepler....

, 7b
Kepler-7b
Kepler-7b is one of the first five planets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It is in the orbit of a star that is not as hot as the Sun, but is significantly larger and is expected to soon reach the end of the main...

 and 8b
Kepler-8b
Kepler-8b is the fifth of the first five exoplanets discovered by NASA's Kepler spacecraft, which aims to discover planets in a region of the sky between the constellations Lyra and Cygnus that transit their host stars. The planet is the hottest of the five...

) larger than Jupiter, and Kepler-7b
Kepler-7b
Kepler-7b is one of the first five planets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It is in the orbit of a star that is not as hot as the Sun, but is significantly larger and is expected to soon reach the end of the main...

 one of the least dense planets found yet. Another discovery, not yet understood, was of at least two objects that are the size of planets, but hotter than their stars. One analysis suggests these objects are white dwarf
White dwarf
A 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.

2010


On 15 June 2010, the Kepler mission released data on all but 400 of the ~156,000 planetary target stars to the public. 706 targets from this first data set have viable exoplanet candidates, with sizes ranging from as small as the Earth to larger than Jupiter. The identity and characteristics of 306 of the 706 targets were given. The released targets included 5 candidate multi-planet systems. Data for the remaining 400 targets with planetary candidates was to be released in February 2011. (For details about this later data release, see the Kepler results for 2011 below.) Nonetheless, the Kepler results, based on the candidates in the list released in 2010, imply that most candidate planets have radii less than half that of Jupiter. The Kepler results also imply that small candidate planets with periods less than 30 days are much more common than large candidate planets with periods less than 30 days and that the ground-based discoveries are sampling the large-size tail of the size distribution. This contradicted older theories which had suggested small and Earth-like planets would be relatively infrequent. Based on the Kepler data, an estimate of around 100 million habitable planets in our galaxy may be realistic. However, some media reports of the TED talk have led to misunderstandings, apparently partly due to confusion concerning the term "Earth-like". By way of clarification, a letter to the Director of the NASA Ames Research Center, for the Kepler Science Council dated August 2, 2010 states, "Analysis of the current Kepler data does not support the assertion that Kepler has found any Earth-like planets."

2011



On 2 February 2011, the
Kepler team announced the results of analysis of the data taken between 2 May and 16 September 2009. They found 1235 planetary candidates circling 997 host stars. (The numbers that follow assume the candidates are really planets, though the official papers call them only candidates. Independent analysis indicates that at least 90% of them are real planets and not false positives.) 68 planets were approximately Earth-size, 288 super-Earth-size, 662 Neptune-size, 165 Jupiter-size, and 19 up to twice the size of Jupiter. 54 planets were within the habitable zone, including 5 less than twice the size of the Earth. In contrast to previous work, roughly 74% of the planets are smaller than Neptune, most likely as a result of previous work finding large planets more easily than smaller ones. The observed planet count versus size increases to a peak at two to three times Earth-size and then declines inversely proportional to area of the planet. The best estimate (as of March, 2011), after accounting for observational biases, was: 5.4% of stars host Earth-size candidates, 6.8% host super-Earth-size candidates, 19.3% host Neptune-size candidates, and 2.55% host Jupiter-size or larger candidates. Multi-planet systems are common; 17% of the host stars have multi-candidate systems, and 33.9% of all the planets are in multiple planet systems.

Follow-ups by other teams


Periodically, the "Kepler" team releases a list of candidates (Kepler Objects of Interest
Kepler Object of Interest
A Kepler Object of Interest is a star observed by the Kepler spacecraft which is suspected of hosting one or more transiting planets. KOIs come from a master list of 150,000 stars which itself is generated from the Kepler Input Catalog . A KOI shows a periodic dimming, indicative of an unseen...

, or KOIs) to the public. Using this information, a team of astronomers collected radial velocity
Radial velocity
Radial 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...

 data using the SOPHIE échelle spectrograph
SOPHIE échelle spectrograph
The SOPHIE échelle spectrograph is a high-resolution echelle spectrograph installed on the 1.93m reflector telescope at the Haute-Provence Observatory located in south-eastern France...

 to confirm the existence of the candidate KOI-428b. Later, the same team then confirmed candidate KOI-423b.

Citizen scientist participation


Kepler mission data has recently been used for the Zooniverse
Zooniverse (citizen science project)
Zooniverse is a citizen science web portal that grew from the original Galaxy Zoo project. It hosts numerous projects which allow users to participate in scientific research from classifying galaxies to collating climate data...

 project "planethunters.org", which allows volunteers to look for transit events in the light curves to identify planets that the computer algorithms might miss. Currently, users may have found 69 candidates that were previously unrecognized by the Kepler mission team. The team has plans to publicly credit amateurs who spot such planets.

Extrasolar planets detected


Kepler has a fixed field of view
Field of view
The field of view is the extent of the observable world that is seen at any given moment....

 (FOV) against the sky. The diagram to the right shows the celestial coordinates and where the detector fields are located, along with the locations of a few bright stars with celestial north at the top left corner. The mission website has a calculator that will determine if a given object falls in the FOV, and if so, where it will appear in the photo detector output data stream. Data on extrasolar planet candidates is submitted to the Kepler Follow-up Program
Kepler Follow-up Program
The Kepler-Follow-up Program, known also as the Kepler Follow-up Observation Program and KFOP, is a program instituted to conduct follow-up observations on Kepler Objects of Interest , or signals noticed by the Kepler spacecraft that may indicate the presence of a planet transiting its host star...

, or KFOP, to conduct follow-up observations.

Kepler has identified two systems containing objects which are smaller and hotter than their parent stars: KOI 74
KOI-74
KOI-74 is an eclipsing binary star in the constellation of Cygnus. The primary star is an A-type main sequence star with a temperature of . It lies in the field of view of the Kepler Mission and was determined to have a companion object in orbit around it which is smaller and hotter than the main...

 and KOI 81
KOI-81
KOI-81 is an eclipsing binary star in the constellation of Cygnus. The primary star is a late B-type or early A-type main sequence star with a temperature of . It lies in the field of view of the Kepler Mission and was determined to have an object in orbit around it which is smaller and hotter than...

. These objects are probably low-mass white dwarf
White dwarf
A 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...

 stars produced by previous episodes of mass transfer
Mass transfer
Mass transfer is the net movement of mass from one location, usually meaning a stream, phase, fraction or component, to another. Mass transfer occurs in many processes, such as absorption, evaporation, adsorption, drying, precipitation, membrane filtration, and distillation. Mass transfer is used...

 in their systems.

In 2010, the Kepler team released a paper which had data for 312 extrasolar planet candidates from 306 separate stars. Only 33.5 days of data were available for most of the candidates. NASA also announced data for another 400 candidates were being withheld to allow members of the Kepler team to perform follow-up observations. The data for these candidates were made public on February 2, 2011.

On February 2, 2011, the Kepler team released a list of 1235 extrasolar planet candidates, including 54 that may be in the "habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

." There were previously only two planets thought to be in the "habitable zone," so these new findings represent an enormous expansion of the potential number of "Goldilocks planets" (planets of the right temperature to support liquid water). All of the habitable zone candidates found thus far orbit stars significantly smaller and cooler than the Sun (habitable candidates around Sun-like stars will take several additional years to accumulate the three transits required for detection). Of all the new planet candidates, 68 are 125% of Earth
Earth
Earth 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...

's size or smaller, or smaller than all previously discovered exoplanets. "Earth-size" and "super-Earth-size" is defined as "less than or equal to 2 Earth radii (Re)" [(or, Rp ≤ 2.0 Re) - Table 5]. Six such planet candidates [namely: KOI 326.01 (Rp=0.85), KOI 701.03 (Rp=1.73), KOI 268.01 (Rp=1.75), KOI 1026.01 (Rp=1.77), KOI 854.01 (Rp=1.91), KOI 70.03 (Rp=1.96) - Table 6] are in the "habitable zone." A more recent study found that one of these candidates (KOI 326.01) is in fact much larger and hotter than first reported.

Based on the latest Kepler findings, astronomer Seth Shostak
Seth Shostak
Seth Shostak is an American astronomer. He grew up in Arlington, VA and earned his physics degree from Princeton University and a Ph.D...

 estimates that "within a thousand light-years of Earth," there are "at least 30,000" habitable planets. Also based on the findings, the Kepler team has estimated that there are "at least 50 billion planets in the Milky Way", of which "at least 500 million" are in the habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

. In March 2011, astronomers at NASA's Jet Propulsion Laboratory
Jet Propulsion Laboratory
Jet Propulsion Laboratory is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. The facility is headquartered in the city of Pasadena on the border of La Cañada Flintridge and Pasadena...

 (JPL) reported that about "1.4 to 2.7 percent" of all sunlike stars are expected to have earthlike planets "within the habitable zone
Habitable zone
In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

s of their stars". This means there are "two billion" of these "Earth analogs" in our own Milky Way galaxy alone. The JPL astronomers also noted that there are "50 billion other galaxies", potentially yielding more than one sextillion "Earth analog" planets if all galaxies have similar numbers of planets to the Milky Way.

Confirmed planets


Below is a table of all extrasolar planetary systems found by Kepler (from the list of extrasolar planets). The first three of the list were already known prior to Kepler, all the others are new discoveries. As of , known extrasolar planets (in planetary systems and multiple-planet systems) are listed in the Extrasolar Planets Encyclopaedia
Extrasolar Planets Encyclopaedia
The Extrasolar Planets Encyclopedia is an astronomy website, founded in Paris, France at the Meudon Observatory by Jean Schneider in February 1995, which maintains a database of all the currently known and candidate extrasolar planets, with individual "note" pages for each planet and a full list...

, ranging from the size of terrestrial planets somewhat larger than Earth to gas giants larger than Jupiter.
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,...

Mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...


(MJ
Jupiter mass
Jupiter mass , is the unit of mass equal to the total mass of the planet Jupiter . Jupiter mass is used to describe masses of the gas giants, such as the outer planets and extrasolar planets. It is also used in describing brown dwarfs....

)
Radius
Radius
In classical geometry, a radius of a circle or sphere is any line segment from its center to its perimeter. By extension, the radius of a circle or sphere is the length of any such segment, which is half the diameter. If the object does not have an obvious center, the term may refer to its...


(RJ)
Orbital
period
Orbital period
The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...


(d
Day
A day is a unit of time, commonly defined as an interval equal to 24 hours. It also can mean that portion of the full day during which a location is illuminated by the light of the sun...

)
Semimajor
axis
(AU
Astronomical unit
An astronomical unit is a unit of length equal to about or approximately the mean Earth–Sun distance....

)
Orbital
ecc.
Inclin.
Inclination
Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...


(°
Degree (angle)
A degree , usually denoted by ° , is a measurement of plane angle, representing 1⁄360 of a full rotation; one degree is equivalent to π/180 radians...

)
Star
Star
A 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...

Constell.
Constellation
In 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....


App.
mag.
Apparent magnitude
The 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...

Distance
(ly)
Spectral
type
Stellar classification
In 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...

Discovery
year
TrES-2b
(Kepler-1b)
1.199 1.272 1.49 0.036 0 83.62 TrES-2
GSC 03549-02811
GSC 03549-02811 A is a yellow main-sequence star similar to our Sun. This star is located approximately 718 light-years away in the constellation of Draco. The apparent magnitude of this star is 11.41, which means it is not visible to the naked eye but can be seen with a medium-sized amateur...

 
Draco
Draco (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...

 
11.41 750 G0V 2006
HAT-P-7b
HAT-P-7b
HAT-P-7b is an extrasolar planet discovered in 2008. It orbits very close to its parent star GSC 03547-01402, and is both larger and more massive than Jupiter. Due to the extreme heat it receives from its star, the dayside temperature is predicted to be 2730 K...


(Kepler-2b)
1.776 1.363 2.20 0.038 0 85.7 HAT-P-7
HAT-P-7
HAT-P-7 is a yellow white dwarf star located about 1044 light-years away in the constellation Cygnus. The apparent magnitude of this star is 10.5, which means it is not visible to the naked eye but can be seen with a small telescope on a clear dark night.-Planetary system:This star has one known...

 
Cygnus
Cygnus (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...

 
10.46 1044 F8 2008
HAT-P-11b
HAT-P-11b
HAT-P-11b is an extrasolar planet orbiting the star HAT-P-11. This planet was discovered by the transit method and submitted for publication on January 2, 2009....


(Kepler-3b)
0.081 0.422 4.89 0.053 0.198 88.5 HAT-P-11
HAT-P-11
HAT-P-11, also designated GSC 03561-02092, is an orange dwarf metal rich star about 123 light-years away in the constellation Cygnus. This star is notable for its relatively large rate of proper motion. The magnitude of this star is about 9, which means it is not visible to the naked eye but can be...

 
Cygnus
Cygnus (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...

 
9.59 123 K4 2009
Kepler-4b
Kepler-4b
Kepler-4b, initially known as KOI 7.01, is an extrasolar planet first detected as a transit by the Kepler spacecraft. Its radius and mass are similar to that of Neptune; however, due to its proximity to its host star, it is substantially hotter than any planet in the Solar System. The planet's...

 
0.077 0.357 3.21 0.046 0 89.76 Kepler-4
Kepler-4
Kepler-4 is a sunlike star located about 1631 light-years away in the constellation Draco. It is in the field of view of the Kepler Mission, a NASA operation purposed with finding Earth-like planets. Kepler-4b, a Neptune-sized planet that orbits extremely close to its star, was discovered in its...

 
Draco
Draco (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...

 
12.6 1794 G0 2010
Kepler-5b
Kepler-5b
Kepler-5b is one of the first five planets discovered by NASA's Kepler spacecraft. It is a Hot Jupiter that orbits a subgiant star that is more massive, larger, and more diffuse than the Sun is...

 
2.114 1.431 3.55 0.051 0 86.3 Kepler-5
Kepler-5
Kepler-5 is a star located in the constellation Cygnus in the field of view of the Kepler Mission, a NASA project aimed at detecting planets in transit of, or passing in front of, their host stars as seen from Earth. One closely orbiting, Jupiter-like planet, named Kepler-5b, has been detected...

 
Cygnus
Cygnus (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...

 
13.9 2010
Kepler-6b
Kepler-6b
Kepler-6b is an extrasolar planet in the orbit of the unusually metal-rich Kepler-6, a star in the field of view of the NASA-operated Kepler spacecraft, which searches for planets that cross directly in front of, or transit, their host stars. It was the third planet to be discovered by Kepler....

 
0.669 1.323 3.23 0.046 0 86.8 Kepler-6
Kepler-6
Kepler-6 is a yellow giant situated in the constellation Cygnus. The star lies within the field of view of the Kepler Mission, which discovered it as part of a NASA-led mission to discover Earth-like planets...

 
Cygnus
Cygnus (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...

 
13.8 2010
Kepler-7b
Kepler-7b
Kepler-7b is one of the first five planets to be confirmed by NASA's Kepler spacecraft, and was confirmed in the first 33.5 days of Kepler's science operations. It is in the orbit of a star that is not as hot as the Sun, but is significantly larger and is expected to soon reach the end of the main...

 
0.433 1.478 4.89 0.062 0 86.5 Kepler-7
Kepler-7
Kepler-7 is a star located in the constellation Lyra in the field of view of the Kepler Mission, a NASA operation in search of Earth-like planets. It is home to the fourth of the first five planets that Kepler discovered; this planet, a Jupiter-size gas giant named Kepler-7b, is as light as styrofoam...

 
Lyra
Lyra
Lyra 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...

 
13.3 2010
Kepler-8b
Kepler-8b
Kepler-8b is the fifth of the first five exoplanets discovered by NASA's Kepler spacecraft, which aims to discover planets in a region of the sky between the constellations Lyra and Cygnus that transit their host stars. The planet is the hottest of the five...

 
0.603 1.419 3.52 0.048 0 84.07 Kepler-8
Kepler-8
| class=F5VKepler-8 is a star located in the constellation Lyra in the field of view of the Kepler Mission, a NASA-led operation tasked with discovering terrestrial planets. The star, which is slightly hotter, larger, and more massive than the Sun, has one gas giant in its orbit, Kepler-8b. This...

 
Lyra
Lyra
Lyra 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...

 
13.9 4338 F5V 2010
Kepler-9b
Kepler-9b
Kepler-9b is one of the first planets discovered outside the solar system by NASA's Kepler Mission. It revolves around the star Kepler-9 within the constellation Lyra. Kepler-9b is the largest of three planets detected in the Kepler system by transit method; its mass is slightly smaller than the...

 
0.252 0.842 19.24 0.14 0.15 88.55 Kepler-9
Kepler-9
Kepler-9 is a sunlike star in the constellation Lyra. It is situated in the Kepler Mission's field of view. Kepler-9 has three confirmed extrasolar planets, all discovered by Kepler using the transit method. The discovery of the first two planets was announced on August 26, 2010, and of the third...

 
Lyra
Lyra
Lyra 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...

 
13.9 2300 G2V 2010
Kepler-9c
Kepler-9c
Kepler-9c is one of the first seven extrasolar planets, exoplanets, discovered by NASA's Kepler Mission, and one of at least two planets orbiting the star Kepler-9. Kepler-9c and Kepler-9b were the first exoplanets confirmed to be transiting their star. The planet's discovery was announced by the...

 
0.171 0.823 38.91 0.225 0.13 88.12 Kepler-9
Kepler-9
Kepler-9 is a sunlike star in the constellation Lyra. It is situated in the Kepler Mission's field of view. Kepler-9 has three confirmed extrasolar planets, all discovered by Kepler using the transit method. The discovery of the first two planets was announced on August 26, 2010, and of the third...

 
Lyra
Lyra
Lyra 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...

 
13.9 2300 G2V 2010
Kepler-9d
Kepler-9d
Kepler-9d, formerly known as KOI-377.03, is a planet in orbit around the sunlike star Kepler-9. Initially discovered by Kepler spacecraft, a terrestrial planet-searching satellite built and operated by NASA, Kepler-9d is most likely a Super-Earth, with an estimated radius approximately 60% larger...

 
0.022? 0.15 1.59 0.027 ? ? Kepler-9
Kepler-9
Kepler-9 is a sunlike star in the constellation Lyra. It is situated in the Kepler Mission's field of view. Kepler-9 has three confirmed extrasolar planets, all discovered by Kepler using the transit method. The discovery of the first two planets was announced on August 26, 2010, and of the third...

 
Lyra
Lyra
Lyra 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...

 
13.9 2300 G2V 2010
Kepler-10b
Kepler-10b
Kepler-10b is the first confirmed terrestrial planet to have been discovered outside the Solar System. Discovered after several months of data collection during the course of the NASA-directed Kepler Mission, which aims to discover Earth-like planets crossing in front of their host stars, the...

 
0.0143 0.127 0.837 0.017 0 84.4 Kepler-10
Kepler-10
Kepler-10, formerly known as KOI-72, is a sunlike star in constellation Draco that lies 173 parsecs away from the Earth. Kepler-10 was targeted by NASA's Kepler spacecraft, as it was seen the first star identified by the Kepler mission as a possible host to a small, transiting exoplanet...

 
Draco
Draco (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...

 
10.96 564 G 2011
Kepler-10c  < 0.063 0.199 45.29 0.241 0 89.65 Kepler-10
Kepler-10
Kepler-10, formerly known as KOI-72, is a sunlike star in constellation Draco that lies 173 parsecs away from the Earth. Kepler-10 was targeted by NASA's Kepler spacecraft, as it was seen the first star identified by the Kepler mission as a possible host to a small, transiting exoplanet...

 
Draco
Draco (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...

 
10.96 564 G 2011
Kepler-11b
Kepler-11b
Kepler-11b is an exoplanet discovered in the orbit of the star Kepler-11 by the Kepler spacecraft, a NASA-led mission to discover Earth-like planets. Kepler-11b is four times more massive and twice as large as Earth, but it has a lighter density estimated at a little over half Earth's, and is...

 
0.01353 0.1762 10.30 0.091 0 88.5 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-11c
Kepler-11c
Kepler-11c is an exoplanet discovered in the orbit of the sun-like star Kepler-11 by the Kepler spacecraft, a NASA telescope aiming to discover Earth-like planets. It is the second planet from its parent star, and is most likely a water planet with a thin hydrogen–helium atmosphere. Kepler-11c...

 
0.0425 0.28175 13.03 0.106 0 89 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-11d
Kepler-11d
Kepler-11d is an exoplanet discovered in the orbit of the sun-like star Kepler-11. It is named for the telescope that discovered it, a NASA spacecraft named Kepler that is designed to detect Earth-like planets by measuring small dips in the brightness of their host stars as the planets cross in front...

 
0.01919 0.3068 22.69 0.159 0 89.3 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-11e
Kepler-11e
Kepler-11e is an exoplanet discovered in the orbit of the sunlike star Kepler-11. It is the fourth of six planets around Kepler-11 discovered by NASA's Kepler spacecraft. Kepler-11e was found by using the transit method, in which a the dimming effect that a planet causes as it crosses in front of...

 
0.02643 0.4043 32.00 0.194 0 88.8 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-11f
Kepler-11f
Kepler-11f is an exoplanet discovered in the orbit of the sunlike star Kepler-11 by NASA's Kepler spacecraft, which searches for planets that transit their host stars. Kepler-11f is the sixth planet from its star, orbiting one fourth of the distance of the Earth from the Sun every 47 days...

 
0.007237 0.2335 46.69 0.25 0 89.4 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-11g  < 0.95 0.3274 118.38 0.462 0 89.8 Kepler-11
Kepler-11
Kepler-11 is a sun-like star slightly larger than the Sun in the constellation Cygnus, located some 2,000 light years from Earth. It is located within the field of vision of the Kepler spacecraft, the satellite that NASA's Kepler Mission uses to detect planets that may be transiting their stars...

 
Cygnus
Cygnus (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...

 
13.7 1999 GV 2011
Kepler-12b
Kepler-12b
Kepler-12b is a Hot Jupiter that orbits G-type star Kepler-12 some 600 parsecs away. The planet has an anomalously large radius that could not be explained by standard models at the time of its discovery, as it is almost 1.7 times Jupiter's size while being 0.4 times Jupiter's mass...

 
0.431 1.695 4.4379637 0.0556 0.01 88.76 Kepler-12
Kepler-12
-References:*http://arxiv.org/pdf/1109.1611v1*http://exoplanet.eu/planet.php?p1=Kepler-12&p2=b&showPubli=yes&sortByDate...

 
Lyra
Lyra
Lyra 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...

 
13.4 1959 G0 2011
Kepler-14b
Kepler-14b
Kepler-14b is an extrasolar planet in orbit around the primary star of the binary Kepler-14 system. It is currently the only planet known to exist in this star system. Kepler-14b is 8.4 times the mass of Jupiter and has a radius 1.14 times that of Jupiter, and it orbits its host star every 6.79 days...

 
8.4 1.136 6.790123 - 0.035 90 Kepler-14
Kepler-14
Kepler-14 is a binary star system targeted by the Kepler spacecraft. It is host to one known planet: the Jupiter-like Kepler-14b. The star system was identified early by Kepler as a possible planetary host, but when imaging revealed that Kepler-14 was a binary star system and not a single star, the...

 
Lyra
Lyra
Lyra 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...

 
12.12 3196 F 2011
Kepler-15b
Kepler-15b
Kepler-15b is a planet discovered by the Kepler spacecraft. It is a hot Jupiter, with a mass of 0.66 +0.08/-0.09 MJ, a radius 0.96 +0.06/-0.07 RJ and a period of about 4.94 days.-References:*http://exoplanet.eu/star.php?st=Kepler-15#a_publi...

 
0.66 0.96 4.9 0.057 0 87.4 Kepler-15
Kepler-15
Kepler-15 is a star that is host to the planet Kepler-15b. It is a G-type main sequence star with a mass of 1.018 M⊙. It is also known as KOI-128, or KIC 11359879.-References:*http://exoplanet.eu/star.php?st=Kepler-15#a_publi...

 
Cygnus
Cygnus (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...

 
G 2011
Kepler-16b
Kepler-16b
Kepler-16b is an extrasolar planet. It is a Saturn-mass planet consisting of half rock and half gas, and it orbits a binary star, Kepler-16, with a period of 229 days...

 
0.33 0.75 228.8 0.7 0 90 Kepler-16
Kepler-16
Kepler-16 is a binary star system in the constellation of Cygnus that was targeted by the Kepler spacecraft. Both stars are smaller than the Sun; the primary, Kepler-16A, is a class K red dwarf, and the secondary, Kepler-16B, is a class M red dwarf...

 
Cygnus
Cygnus (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...

 
~ 200 K/M 2011


The planets KOI-423b, KOI-428b. and KOI-196b KOI=Kepler Object of Interest
Kepler Object of Interest
A Kepler Object of Interest is a star observed by the Kepler spacecraft which is suspected of hosting one or more transiting planets. KOIs come from a master list of 150,000 stars which itself is generated from the Kepler Input Catalog . A KOI shows a periodic dimming, indicative of an unseen...

.

Kepler Input Catalog



The Kepler Input Catalog (or KIC) is a publicly searchable database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...

 of roughly 13.2 million targets used for the Kepler Spectral Classification Program and Kepler. The catalog alone is not used for finding Kepler targets, because only a portion (about 1/3 of the catalog) can be observed by the spacecraft.

See also

  • List of planetary systems
  • NASA Star and Exoplanet Database
    NASA Star and Exoplanet Database
    The NASA Star and Exoplanet Database is an on-line astronomical stellar and exoplanet catalog and data service that collates and cross-correlates astronomical data and information on exoplanets and their host stars. NStED is dedicated to collecting and serving important public data sets involved...

  • PlanetQuest
    PlanetQuest
    PlanetQuest is a grid computing project for discovering new planets and classifying stars from Earth-based observatories' images.-Overview:The PlanetQuest project is currently still under development, and will utilize the BOINC platform.To search for new planets, PlanetQuest developed the Transit...

  • High Accuracy Radial Velocity Planet Searcher
    High Accuracy Radial Velocity Planet Searcher
    The High Accuracy Radial velocity Planet Searcher is a high-precision echelle spectrograph installed in 2002 on ESO's 3.6m telescope at La Silla Observatory in Chile. The first light was achieved in February 2003...

  • SuperWASP
    SuperWASP
    SuperWASP is an international academic organisation performing an ultra-wide angle search for transiting extrasolar planets with the aim of covering the entire sky down to ~15th magnitude.-Equipment:...

  • Trans-Atlantic Exoplanet Survey
    Trans-Atlantic Exoplanet Survey
    The Trans-atlantic Exoplanet Survey or TrES, uses three 4-inch telescopes located at Lowell Observatory, Palomar Observatory, and the Canary Islands to locate exoplanets. It was made using the network of small, relatively inexpensive telescopes designed to look specifically for planets orbiting...

     (TrES)
  • Automated Planet Finder
    Automated Planet Finder
    The Automated Planet Finder Telescope is a fully automated 2.4-meter optical telescope under construction at Lick Observatory designed to search for extrasolar planets in the range of five to twenty times the mass of the Earth. The instrument will examine 25 stars per night. Over a decade, the...

  • HATNet Project
    HATNet Project
    The Hungarian Automated Telescope Network project is a network of six small fully automated "HAT" telescopes. The scientific goal of the project is to detect and characterize extrasolar planets using the transit method. This network is used also to find and follow bright variable stars...

  • COROT
    Corot
    Corot may refer to:* Jean-Baptiste-Camille Corot, French landscape painter * COROT, a space mission with the dual aims of finding extrasolar planets and performing asteroseismology* COROT-7, a dwarf star in the Monoceros constellation...

  • PLATO
    PLATO (spacecraft)
    PLAnetary Transits and Oscillations of stars is a European Space Agency-proposed space observatory that will use a group of photometers to discover and characterize extrasolar planets of all sizes and kinds around cool dwarf and subgiant stars...

  • Eddington
  • Darwin
  • Space Interferometry Mission
    Space Interferometry Mission
    The Space Interferometry Mission, or SIM, also known as SIM Lite , was a planned space telescope developed by the U.S. National Aeronautics and Space Administration , in conjunction with contractor Northrop Grumman...

  • Terrestrial Planet Finder
    Terrestrial Planet Finder
    The Terrestrial Planet Finder was a proposed project by NASA to construct a system of telescopes for detecting extrasolar terrestrial planets. TPF was postponed several times and finally cancelled...


External links