Gliese 12

Gliese 12

Artist's impression of Gliese 12 and its planet (foreground)
Observation data Epoch J2000      Equinox J2000
Constellation	Pisces[1]
Right ascension	00h 15m 49.24231s[2]
Declination	+13° 33′ 22.3163″[2]
Apparent magnitude (V)	12.6[3]
Characteristics
Evolutionary stage	main sequence
Spectral type	M4V[4]
Apparent magnitude (V)	12.600±0.04[3]
Apparent magnitude (R)	12.296±0.08[3]
Apparent magnitude (G)	11.399±0.003[2]
Apparent magnitude (J)	8.619±0.020[3]
Apparent magnitude (H)	8.068±0.026[3]
Apparent magnitude (K)	7.807±0.020[3]
Astrometry
Radial velocity (Rv)	51.04±0.26[2] km/s
Proper motion (μ)	RA: 618.065 mas/yr[2] Dec.: 329.446 mas/yr[2]
Parallax (π)	82.1938 ± 0.0326 mas[2]
Distance	39.68 ± 0.02 ly (12.166 ± 0.005 pc)
Details[5]
Mass	0.2414±0.0060 M☉
Radius	0.2617+0.0058 −0.0070 R☉
Luminosity (bolometric)	0.00728±0.00015 L☉
Surface gravity (log g)	5.21±0.07 cgs
Temperature	3,296+48 −36 K
Metallicity [Fe/H]	−0.32±0.06 dex
Rotation	85 days
Rotational velocity (v sin i)	<2 km/s
Age	7.0+2.8 −2.2[6] Gyr
Other designations
GJ 12, G 32-5, L 1154-29, LHS 1050, LP 464-42, LTT 10083, NLTT 786, PLX 42, TOI-6251, TIC 52005579, 2MASS J00154919+1333218[3]
Database references
SIMBAD	data

Gliese 12 (GJ 12) is a red dwarf star located 39.7 light-years (12.2 parsecs) away in the constellation Pisces. It has about 24% the mass and 26% the radius of the Sun, and a temperature of about 3,296 K (3,023 °C; 5,473 °F). It is an inactive star and hosts one known exoplanet.^[5]

The transiting exoplanet Gliese 12 b was discovered by TESS, and two independent studies confirming it as a planet were published in May 2024.^[5][6] Gliese 12 b is similar in size to Earth and Venus, and completes an orbit around its star every 12.8 days. Its mass is poorly constrained but is known to be less than 4 times that of Earth.^[5]

Along with the planets of TRAPPIST-1 and LHS 1140 b, Gliese 12 b is one of the nearest known relatively temperate transiting exoplanets, and so is a promising target for the James Webb Space Telescope to determine whether it has retained an atmosphere.^[7] Gliese 12 b orbits slightly closer than the inner edge of its star's habitable zone, with an insolation between those of Earth and Venus.^[6] Its equilibrium temperature, assuming an albedo of zero, is 315 K (42 °C; 107 °F); if it has an atmosphere, the surface temperature would be greater than this.^[5]