Kepler-438

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]

Kepler-438

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

Planetary system

The system has one confirmed planet. However, transit timing observations of Kepler-438b indicate the possible presence of additional planets.^[8]

The Kepler-438 planetary system^[5][3]

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🜨