Kepler-38 is a binary star system in the constellation Lyra. These stars, called Kepler-38A and Kepler-38B have masses of 95% and 25% solar masses respectively. The brighter star is spectral class G while the secondary has spectral class M. They are separated by 0.147 AU, and complete an eccentric orbit around a common center of mass every 18.8 days.[2]

Kepler-38
Observation data
Epoch J2000      Equinox J2000
Constellation Lyra
Right ascension 19h 07m 19.2813s[1]
Declination +42° 16′ 45.121″[1]
Characteristics
Spectral type G V[2] / M[3]
Astrometry
Proper motion (μ) RA: −4.575(14) mas/yr[1]
Dec.: −13.219(14) mas/yr[1]
Parallax (π)0.8546 ± 0.0119 mas[1]
Distance3,820 ± 50 ly
(1,170 ± 20 pc)
Orbit
PrimaryKepler-38A
CompanionKepler-38B
Period (P)18.79537
Semi-major axis (a)0.1469
Eccentricity (e)0.1032
Details
Kepler-38A
Mass0.949 M
Radius1.757 R
Temperature5640 K
Metallicity-0.11
Kepler-38B
Mass0.249 M
Radius0.2724 R
Metallicity-0.11
Other designations
KOI-1740, KIC 6762829, 2MASS J19071928+4216451[4]
Database references
SIMBADdata
KICdata

Planetary system

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In 2012, a circumbinary Neptune-sized planet was found transiting the brighter star. Follow-up radial velocity measurements did not give sufficient information to constrain the mass of the planet. The planet was confirmed via transit duration variation method.

It is likely that additional planets in the habitable zone exist, including rocky terrestrial planets, according to simulations of the formation of the Kepler-38 system; furthermore, the orbits of any such planets are probably stable.[5]

The Kepler-38 planetary system
Companion
(in order from star)
Mass Semimajor axis
(AU)
Orbital period
(days)
Eccentricity Inclination Radius
b 0.4644 105.595 0.39 RJ

See also

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References

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  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b Orosz, Jerome A.; et al. (2012), "THE NEPTUNE-SIZED CIRCUMBINARY PLANET KEPLER-38b", The Astrophysical Journal, 758 (2): 87, arXiv:1208.3712, Bibcode:2012ApJ...758...87O, doi:10.1088/0004-637X/758/2/87, S2CID 119226095
  3. ^ "Notes for star Kepler-38(AB)". Extrasolar Planets Encyclopaedia. 2012. Retrieved 29 April 2013.[dead link]
  4. ^ "Kepler-38". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 January 2017.
  5. ^ Macau, E E N.; Domingos, R. C.; Izidoro, A.; Amarante, A.; Winter, O. C.; Barbosa, G. O. (2020), "Earth-size planet formation in the habitable zone of circumbinary stars", Monthly Notices of the Royal Astronomical Society, 494: 1045–1057, arXiv:2003.11682, doi:10.1093/mnras/staa757, S2CID 214667061