K2-3

K2-3, also known as EPIC 201367065,^[8] is a red dwarf star with three known planets. It is on the borderline of being a late orange dwarf/K-type star, but because of its temperature, it is classified as a red dwarf (4,000 K is typically the division line between spectral class M and K).

K2-3

Observation data Epoch J2000      Equinox J2000
Constellation	Leo[1]
Right ascension	11h 29m 20.39171s[2]
Declination	−01° 27′ 17.2817″[2]
Apparent magnitude (V)	12.168±0.009[3]
Characteristics
Evolutionary stage	Main sequence[4]
Spectral type	M0±0.5[4]
Apparent magnitude (J)	9.421±0.027[5]
Apparent magnitude (H)	8.805±0.044[5]
Apparent magnitude (K)	8.561±0.021[5]
Variable type	Planetary transit[4]
Astrometry
Radial velocity (Rv)	30.24±0.46[2] km/s
Proper motion (μ)	RA: 94.116 mas/yr[2] Dec.: −78.003 mas/yr[2]
Parallax (π)	22.7374±0.0220 mas[2]
Distance	143.4 ± 0.1 ly (43.98 ± 0.04 pc)
Details[6]
Mass	0.549+0.029 −0.027 M☉
Radius	0.546+0.018 −0.016 R☉
Luminosity (bolometric)	0.0587+0.0018 −0.0019 L☉
Surface gravity (log g)	4.704+0.023 −0.026 cgs
Temperature	3844+61 −63 K
Metallicity [Fe/H]	−0.157+0.075 −0.080 dex
Rotation	40±2 d[7]
Age	6.9±4.7 Gyr
Other designations
Gaia DR3 3796690380302214272, EPIC 201367065, 2MASS J11292037-0127173, WISE J112920.45-012718.0[8]
Database references
SIMBAD	data

At a distance of 143 light-years (44 parsecs),^[2] the star's proximity means it is bright enough to make it feasible for astronomers to study the planets' atmospheres to determine whether they are like Earth's atmosphere and possibly conducive to life.

Planetary system

K2-3 has three confirmed exoplanets, discovered in 2015.^[4] All are low-density super-Earths or sub-Neptunes, with the outermost orbiting near the inner edge of the habitable zone.^[9][6]

The K2-3 planetary system^[6][10]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	5.11+0.65 −0.64 M🜨	0.0778±0.0026	10.054626(0)	<0.094	89.588+0.12 −0.100°	2.078+0.076 −0.067 R🜨
c	2.68±0.85 M🜨	0.1414±0.0047	24.646582(39)	<0.095	89.905+0.066 −0.088°	1.582+0.057 −0.051 R🜨
d	<1.6 M🜨	0.2097±0.0070	44.556456(97)	<0.097	89.788+0.033 −0.029°	1.458+0.056 −0.051 R🜨