Kepler-23

Kepler-23 is a G-type main-sequence star about 2,860 light-years (880 parsecs) away in the northern constellation of Cygnus, the swan. With an apparent visual magnitude of 13.5,^[3] it is too faint to be seen with the naked eye. This star is similar in mass and temperature to the Sun, but is larger and more luminous.^[5][4] Kepler-23 is orbited by three known exoplanets.^[6]

Kepler-23

Kepler-23 compared to the Sun
Observation data Epoch J2000      Equinox J2000
Constellation	Cygnus[1]
Right ascension	19h 36m 52.5355s[2]
Declination	+49° 28′ 45.253″[2]
Apparent magnitude (V)	13.547[3]
Characteristics
Spectral type	G2V[3]
Astrometry
Radial velocity (Rv)	−26.97±2.38[2] km/s
Proper motion (μ)	RA: 2.275(12) mas/yr[2] Dec.: 3.879(14) mas/yr[2]
Parallax (π)	1.1395±0.0101 mas[2]
Distance	2,860 ± 30 ly (878 ± 8 pc)
Details
Mass	1.078±0.077[4] M☉
Radius	1.548±0.048[4] R☉
Luminosity	~2.3[5] L☉
Surface gravity (log g)	4.00±0.14[5] cgs
Temperature	5828±100[4] K
Metallicity [Fe/H]	−0.09±0.14[5] dex
Age	4-8[5] Gyr
Other designations
Gaia DR2 2135019107451751168, KOI-168, KIC 11512246, GSC 03564-01806, 2MASS J19365254+4928452[3]
Database references
SIMBAD	data
KIC	data

Planetary system

Three transiting exoplanets orbit this star, discovered using the Kepler space telescope. Two planets, Kepler-23b and Kepler-23c, were discovered in 2011 and were confirmed in 2012.^[5] A third planet, Kepler-23d, was confirmed in 2014 as part of a study validating hundreds of Kepler candidates.^[7] All three planets are between Earth and Neptune in size (sub-Neptunes), and their masses have been measured via transit-timing variations, showing that they have lower densities than Earth.^[4]

The Kepler-23 planetary system^[8][4]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	2.56+0.43 −0.40 M🜨	0.075	7.106995(73)	0.017+0.019 −0.014	—	1.638±0.047 R🜨
c	7.81+1.32 −1.20 M🜨	0.099	10.742434(39)	0.021+0.009 −0.014	—	3.005±0.074 R🜨
d	4.44+1.30 −1.21 M🜨	0.124	15.27429(17)	0.010+0.014 −0.008	—	2.206±0.057 R🜨