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Observation data
Epoch J2000      Equinox J2000
Constellation Cygnus
Right ascension  19h 04m 58.4221s[1]
Declination +50° 02′ 25.271″[1]
Apparent magnitude (V) 13.4[2]
Proper motion (μ) RA: 3.053±0.025[1] mas/yr
Dec.: 3.235±0.024[1] mas/yr
Parallax (π)1.1057 ± 0.0125[1] mas
Distance2,950 ± 30 ly
(900 ± 10 pc)
Spectral type G0[2]
Mass1.166±0.054 M
Radius1.483±0.029 R
Temperature5947±100 K
Metallicity [Fe/H]0.07 (± 0.04) dex
Rotational velocity (v sin i)2.7±0.5[3] km/s
Age4.0±0.4 Gyr
Other designations
KIC 11804465, KOI-20, GSC 03549-00844, 2MASS J19045842+5002253[3]
Database references

Kepler-12 is a star with a transiting planet Kepler-12b in a 4-day orbit.


Kepler-12, known also as KIC 11804465 in the Kepler Input Catalog, is an early G-type to late F-type star. This corresponds strongly with a sunlike dwarf star nearing the end of the main sequence, and is about to become a red giant.[4] Kepler-12 is located approximately 900 parsecs (2,950 light years) away from Earth. The star also has an apparent magnitude of 13.438, which means that it cannot be seen from Earth with the unaided eye.[2]

The star is slightly more massive, slightly more iron-rich and slightly hotter than the Sun. However, Kepler-12 is larger, with a radius of 1.483 times the Sun's radius.[2]

Planetary system[edit]

The one currently known planet is a hot Jupiter with a radius 1.7 times that of Jupiter but less than half the mass.[5]

The Kepler-12 planetary system[5][4]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b 0.432+0.053
4.4379637±0.0000002 0 88.796+0.088


  1. ^ a b c d e 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 catalog entry
  2. ^ a b c d e "Notes on Kepler-12 b". Retrieved 29 December 2016.
  3. ^ a b "Kepler-12". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 29 December 2016.
  4. ^ a b Fortney, Jonathan J.; et al. (2011). "Discovery and Atmospheric Characterization of Giant Planet Kepler-12b: An Inflated Radius Outlier". The Astrophysical Journal Supplement Series. 197. 9. arXiv:1109.1611. Bibcode:2011ApJS..197....9F. doi:10.1088/0067-0049/197/1/9.
  5. ^ a b Esteves, Lisa J.; Mooij, Ernst J. W. De; Jayawardhana, Ray (2015). "Changing Phases of Alien Worlds: Probing Atmospheres Of Kepler planets with High-Precision Photometry". The Astrophysical Journal. 804 (2). 150. arXiv:1407.2245. Bibcode:2015ApJ...804..150E. doi:10.1088/0004-637X/804/2/150.

Coordinates: Sky map 19h 04m 58s, +50° 02′ 25″