20 Leonis Minoris

20 Leonis Minoris is a binary star system in the northern constellation of Leo Minor. It is faintly visible to the naked eye, having an apparent visual magnitude of +5.4.^[2] Based upon an annual parallax shift of 66.996 mas, it is located 48.7 light-years from the Sun. The star has a relatively high proper motion^[3] and is moving away from the Sun with a radial velocity of +56 km/s.^[6] The system made its closest approach about 150,000 years ago when it came within 32.2 ly (9.86 pc).^[14]

20 Leonis Minoris

Observation data Epoch J2000      Equinox J2000
Constellation	Leo Minor
Right ascension	10h 01m 00.65688s[1]
Declination	+31° 55′ 25.2130″[1]
Apparent magnitude (V)	+5.40[2]
Characteristics
Spectral type	G3 Va Hδ1[3] + M7 V[4]
U−B color index	+0.27[5]
B−V color index	+0.65[5]
Astrometry
Radial velocity (Rv)	+55.96±0.09[6] km/s
Proper motion (μ)	RA: −528.871(92) mas/yr[1] Dec.: −429.376(74) mas/yr[1]
Parallax (π)	66.9958±0.0921 mas[1]
Distance	48.68 ± 0.07 ly (14.93 ± 0.02 pc)
Absolute magnitude (MV)	4.46[7]
Details
20 LMi A
Mass	0.967±0.010[8] M☉
Radius	1.237±0.019[8] R☉
Luminosity	1.365±0.014[8] L☉
Surface gravity (log g)	4.25±0.02[8] cgs
Temperature	5,735±5.6[9] K
Metallicity [Fe/H]	0.20±0.02[8] dex
Rotation	10.64±0.14 d[2]
Rotational velocity (v sin i)	2.4±0.5[8] km/s
Age	6.2–7.7[10] Gyr
20 LMi B
Mass	0.11[11] M☉
Temperature	3,106(54)[12] K
Metallicity [Fe/H]	0.00(9)[12] dex
Rotation	19.2687 d[4]
Other designations
20 LMi, BD+32° 1964, FK5 1258, GJ 376, HD 86728, HIP 49081, HR 3951, SAO 61808, LHS 2216, LTT 12671[13]
Database references
SIMBAD	data

The primary member of this system is a G-type main-sequence star with a stellar classification of G3 Va H_δ1.^[3] It has 12% more mass and a 25% larger radius than the Sun. The star is about seven^[10] billion years old and is spinning with a rotation period of 10.6 days.^[2] The small companion is an active red dwarf star that has a relatively high metallicity.^[15] The two stars are currently separated by 14.5 arc seconds, corresponding to a projected separation of 2016 AU.^[11]

Planetary system

Artist's impression of 20 Leonis Minoris b orbiting its star.^[16]

A candidate exoplanet orbiting 20 Leonis Minoris A (HD 86728) was first detected in 2020,^[17] and confirmed in 2024 as the first discovery of the NEID Earth Twin Survey (NETS). With a minimum mass of 9.2 M_🜨 and an orbital period of 31 days, this is most likely a hot Neptune-type planet.^[8]

The 20 Leonis Minoris A planetary system^[8]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥9.16+0.55 −0.56 M🜨	0.1916+0.00065 −0.00066	31.1503+0.0062 −0.0066	0.064+0.065 −0.044	—	—