Kepler-39

Kepler-39 (2MASS J19475046+4602034) is an F-type main sequence star located in the constellation Cygnus. It is located about 3,500 light-years (1,070 parsecs) away.^[1] One known substellar companion orbits it, Kepler-39b.^[5]

Kepler-39

Observation data Epoch J2000      Equinox J2000
Constellation	Cygnus
Right ascension	19h 47m 50.4746s[1]
Declination	+46° 02′ 03.500″[1]
Apparent magnitude (V)	14.3[2]
Characteristics
Spectral type	F7V[3]
Astrometry
Proper motion (μ)	RA: 3.894(18) mas/yr[1] Dec.: −2.345(17) mas/yr[1]
Parallax (π)	0.9316 ± 0.0139 mas[1]
Distance	3,500 ± 50 ly (1,070 ± 20 pc)
Details[3]
Mass	1.29+0.06 −0.07 M☉
Radius	1.40±0.10 R☉
Surface gravity (log g)	4.25±0.06 cgs
Temperature	6350±100 K
Metallicity [Fe/H]	0.10±0.14 dex
Rotation	4.464±0.013 days[4]
Rotational velocity (v sin i)	16±2.5 km/s
Age	2.1+0.8 −0.9 Gyr
Other designations
KOI-423, KIC 9478990, Gaia DR2 2080168561154800384, 2MASS J19475046+4602034
Database references
SIMBAD	data
KIC	data

Planetary system

Kepler-39b is generally considered a brown dwarf rather than a planet since it does not meet the standard definition of planet. Some authorities such as the Extrasolar Planets Encyclopaedia and the NASA Exoplanet Archive include it among their list of confirmed planets.^[2][6]

The Kepler-39 planetary system^[3]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	20.1+1.3 −1.2 MJ	0.164±0.003	21.087210±0.000037	0.112±0.057	89.07±0.22°	1.24+0.09 −0.10 RJ

References

1. 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. "Kepler-39 b". Extrasolar Planets Encyclopaedia. Retrieved 2018-06-09.
3. Bonomo, A. S.; et al. (2015). "Improved parameters of seven Kepler giant companions characterized with SOPHIE and HARPS-N". Astronomy and Astrophysics. 575. A85. arXiv:1501.02653. Bibcode:2015A&A...575A..85B. doi:10.1051/0004-6361/201323042. S2CID 119230291.
4. McQuillan, A.; Mazeh, T.; Aigrain, S. (2013). "Stellar Rotation Periods of The Kepler objects of Interest: A Dearth of Close-In Planets Around Fast Rotators". The Astrophysical Journal Letters. 775 (1). L11. arXiv:1308.1845. Bibcode:2013ApJ...775L..11M. doi:10.1088/2041-8205/775/1/L11. S2CID 118557681.
5. Bouchy, F.; et al. (2011). "SOPHIE velocimetry of Kepler transit candidates. III. KOI-423b: an 18 M_Jup transiting companion around an F7IV star". Astronomy and Astrophysics. 533. A83. arXiv:1106.3225. Bibcode:2011A&A...533A..83B. doi:10.1051/0004-6361/201117095. S2CID 62836749.
6. "Kepler-39 b". NASA Exoplanet Archive. Retrieved 2018-06-09.