| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lyra[1] |
| Right ascension | 19h 07m 19.2813s[2] |
| Declination | +42° 16′ 45.121″[2] |
| Characteristics | |
| Spectral type | G V[3] / M[4] |
| Astrometry | |
| Proper motion (μ) | RA: −4.575(14)mas/yr[2] Dec.: −13.219(14)mas/yr[2] |
| Parallax (π) | 0.8546±0.0119 mas[2] |
| Distance | 3,820 ± 50 ly (1,170 ± 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 | |
| KOI-1740,KIC 6762829,2MASS J19071928+4216451[5] | |
| Database references | |
| SIMBAD | data |
| KIC | data |
Kepler-38 is abinary star system in theconstellationLyra. 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 0.147AU, and complete an eccentric orbit around a common center of mass every 18.8 days.[3]
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.[6]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | — | 0.4644 | 105.595 | — | — | 0.39 RJ |