Gliese 22

Gliese 22

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Cassiopeia
Gliese 22 A
Right ascension	00h 32m 29.4336s
Declination	+67° 14′ 08.409″
Apparent magnitude (V)	10.29
Gliese 22 B
Right ascension	00h 32m 29.575s
Declination	+67° 14′ 04.63″
Apparent magnitude (V)	12.19
Gliese 22 C
Right ascension	00h 32m 29.4s
Declination	+67° 14′ 08″
Apparent magnitude (V)	13.2
Characteristics
Spectral type	M2.5Ve / M3V
U−B color index	1.16
B−V color index	1.54
R−I color index	0.99
Variable type	Flare stars
Astrometry
Radial velocity (Rv)	10 km/s
Proper motion (μ)	RA: 1739.0 mas/yr Dec.: -224.93 mas/yr
Parallax (π)	99.35 ± 2.17 mas
Distance	32.8 ± 0.7 ly (10.1 ± 0.2 pc)
Absolute magnitude (MV)	11.83
Orbit
Companion	Gliese 22 B
Period (P)	320 yr
Semi-major axis (a)	4"
Inclination (i)	140°
Orbit
Companion	Gliese 22 C
Period (P)	16 yr
Semi-major axis (a)	0.5"
Details
Mass	0.4 M☉
Radius	0.5 R☉
Luminosity	0.04 L☉
Temperature	2000–3500 K
Other designations
2MASS J00322970+6714080, BD+66° 34, CCDM J00325+6714, Gl 22, HIP 2552, LFT 47, V547 Cassiopeiae
Database references
SIMBAD	data
Exoplanet Archive	data
Extrasolar Planets Encyclopaedia	data

Gliese 22, also catalogued V547 Cassiopeiae, is a hierarchical star system approximately 33 light-years away in the constellation of Cassiopeia. The system consists of two red dwarf stars, Gliese 22A and Gliese 22B in an outer orbit of about 320 years, and a brown dwarf, Gliese 22C, which orbits Gliese 22A in about 16 years. As of 2008, it was announced that a possible extrasolar planet, Gliese 22B b, or brown dwarf orbits Gliese 22B but this is currently unconfirmed.

Planetary system

The Gliese 22 planetary system

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b (unconfirmed)	16 MJ	—	5,500	0	—	—