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Kepler-22 diagram.jpg
A diagram of the Kepler-22b System, compared to our Inner Solar System.
Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus[1]
 19h 16m 52.1904s[2]
Declination +47° 53′ 03.948″[2]
Spectral type G5V[4]
Proper motion (?) RA: [2] mas/yr
Dec.: [2] mas/yr
Parallax (?)5.1088 ± 0.0242[2] mas
Distance638 ± 3 ly
(195.7 ± 0.9 pc)
Absolute magnitude (MV)~5.27
Absolute bolometric
Mass[3] M
Radius[3] R
Luminosity[3] L
Luminosity (bolometric)0.8 L
Luminosity (visual, LV)~0.67 L
Temperature[3] K
Metallicity [Fe/H][3] dex
Rotational velocity (v sin i)[3] km/s
Other designations
, , , [5]
Database references

Kepler-22 is a star in the northern constellation of Cygnus, the swan, that is orbited by a planet found to be unequivocally within the star's habitable zone. It is located at the celestial coordinates: Right Ascension  19h 16m 52.2s, Declination +47° 53′ 4.2″.[6] With an apparent visual magnitude of 11.7,[3] this star is too faint to be seen with the naked eye. It can be viewed with a telescope having an aperture of at least 4 in (10 cm).[7] The estimated distance to Kepler-22 is 638 light-years (196 parsecs).[2]

Kepler-22 is slightly smaller and cooler than the Sun,[8] with a lower abundance of elements having more mass than helium.[3] It has a spectral type of G5V, while the luminosity class remains undetermined.[4] This star is radiating 79%[3] of the Sun's luminosity from its outer atmosphere at an effective temperature of 5,518 K,[3] giving it the yellow-hued glow of a G-type star.[9] A projected rotational velocity of 0.6 km/s[3] suggests it has a low period of rotation.

Planetary system

On December 5, 2011, scientists from the Kepler mission announced that a possible Earthlike world (Kepler-22b) had been discovered orbiting in the star's habitable zone by NASA's Kepler spacecraft.[10] This was significant in that it was the first relatively Earth-sized extrasolar planet (about twice as big)[10] confirmed to be orbiting within a star's habitable zone.[11]

The Kepler-22 planetary system[4]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b < 0.11 MJ 0.849 ± 0.018 289.8623 +0.016
-- -- 2.4 R?


  1. ^ "Cygnus - constellation boundary", The Constellations, International Astronomical Union, retrieved
  2. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051.Gaia Data Release 2 Vizier catalog entry
  3. ^ a b c d e f g h i j k l Kepler-22b, NASA Ames Research Center, retrieved
  4. ^ a b c Schneider, Jean, "Star: Kepler-22", Extrasolar Planets Encyclopaedia, Paris Observatory, retrieved
  5. ^ "GSC 03546-02301 -- Star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved
  6. ^ "Kepler Discoveries". 2011-12-05.
  7. ^ Sherrod, P. Clay; Koed, Thomas L. (2003), A Complete Manual of Amateur Astronomy: Tools and Techniques for Astronomical Observations, Astronomy Series, Courier Dover Publications, p. 9, ISBN 0486428206
  8. ^ "Kepler Confirms First Planet in Habitable Zone of Sun-Like Star". Universe Today. 2011-12-05.
  9. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved
  10. ^ a b Boyle, Rebecca (December 5, 2011). "Kepler Team Confirms First Earth-like planet in a habitable zone, And Finds 1,094 More Worlds". Popular Science. Retrieved 2011.
  11. ^ "NASA Telescope Confirms Alien Planet in Habitable Zone". 2011-12-05.

Coordinates: Sky map19h 16m 52.2s, +47° 53? 4.2?

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