Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Lyra [1] |
Right ascension | 18h 46m 34.9968s [2] |
Declination | +41° 57′ 03.934″ [2] |
Apparent magnitude (V) | 15.0 [3] |
Characteristics | |
Variable type | Flare star [4] |
Astrometry | |
Proper motion (μ) | RA: −16.649(115) mas/yr [2] Dec.: −5.614(111) mas/yr [2] |
Parallax (π) | 5.5592±0.0984 mas [2] |
Distance | 590 ± 10 ly (180 ± 3 pc) |
Absolute magnitude (MV) | 9.55+0.54 −0.44 [5] |
Details [5] | |
Mass | 0.544+0.061 −0.041 M☉ |
Radius | 0.52+0.061 −0.038 R☉ |
Luminosity | 0.044+0.017 −0.012 L☉ |
Surface gravity (log g) | 4.74 cgs |
Temperature | 3748±112 K |
Metallicity [Fe/H] | 0.16±0.14 dex |
Age | 4.4+0.7 −0.8 Gyr |
Other designations | |
KIC 6497146, KOI-3284, 2MASS J18463499+4157039 [6] | |
Database references | |
SIMBAD | data |
KIC | data |
Kepler-438 is a red dwarf in the constellation Lyra, about 590 light years from Earth. [2] It is notable for its planetary system, which includes Kepler-438b, a possibly Earth-size planet within Kepler-438's habitable zone. Kepler-438 is a flare star that undergoes random, dramatic increases in brightness due to flare activity. It emits strong superflares every few hundred days, with each flare being stronger than the most powerful flare recorded on the Sun. [7]
The system has one confirmed planet. However, transit timing observations of Kepler-438b indicate the possible presence of additional planets. [8]
Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | — | 0.166 +0.051 −0.042 | 35.23319 +0.00025 −0.00029 | 0.03 +0.10 −0.03 | 89.86 +0.14 −0.32 ° | 1.12 +0.16 −0.17 R🜨 |