Kepler-38
Kepler-38 is a binary star system. 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.[4]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra |
| Right ascension | 19h 07m 19.2814s[1] |
| Declination | +42° 16′ 45.120″[1] |
| Characteristics | |
| Spectral type | G / M[2] |
| Astrometry | |
| Proper motion (μ) | RA: −4.648±0.026[1] mas/yr Dec.: −13.159±0.025[1] mas/yr |
| Parallax (π) | 0.8225 ± 0.0145[1] mas |
| Distance | 3,970 ± 70 ly (1,220 ± 20 pc) |
| Orbit | |
| Primary | Kepler-38A |
| Companion | Kepler-38B |
| Period (P) | 18.79537 |
| Semi-major axis (a) | 0.1469 |
| Eccentricity (e) | 0.1032 |
| Details | |
| Kepler-38A | |
| Mass | 0.949 M☉ |
| Radius | 1.757 R☉ |
| Temperature | 5640 K |
| Metallicity | -0.11 |
| Kepler-38B | |
| Mass | 0.249 M☉ |
| Radius | 0.2724 R☉ |
| Metallicity | -0.11 |
| Other designations | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Planetary system
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.
Numerical simulation of formation of planetary system Kepler-38 has shown the formation of additional rocky planets in the habitable zone is highly likely, and these planetary orbits are stable.[5]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | 0.4644 | 105.595 | — | — | 0.39 RJ |
References
- 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 DR2 record for this source at VizieR.
- "Notes for star Kepler-38(AB)". Extrasolar Planets Encyclopaedia. 2012. Retrieved 29 April 2013.
- "Kepler-38". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 4 January 2017.
- The Neptune-Sized Circumbinary Planet Kepler-38b, 2012, arXiv:1208.3712
- 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