Gliese 22

Gliese 22, also catalogued V547 Cassiopeiae or ADS 440, is a hierarchical star system approximately 33 light-years (10.1 parsecs) away in the constellation of Cassiopeia. The system consists of pair of red dwarf stars, Gliese 22A and Gliese 22C, orbited by a third red dwarf Gliese 22B in an outer orbit of about 223 years.

ConstellationCassiopeia^[2]

Right ascension00^h 32^m 29.4336^{s[citation needed]}

Declination+67° 14′ 08.409″^{[citation needed]}

Apparentmagnitude(V)10.29^{[citation needed]}

Quick facts Constellation, Right ascension ...

Gliese 22

A blue band light curve for a flare of Gliese 22A, adapted from Pettersen (1975)[1]
Observation data Epoch J2000.0      Equinox ICRS
Constellation	Cassiopeia[2]
Gliese 22 A
Right ascension	00h 32m 29.4336s[citation needed]
Declination	+67° 14′ 08.409″[citation needed]
Apparent magnitude (V)	10.29[citation needed]
Gliese 22 B
Right ascension	00h 32m 29.58665s[3]
Declination	+67° 14′ 03.7983″[3]
Apparent magnitude (V)	12.19
Gliese 22 C
Right ascension	00h 32m 29.4s[citation needed]
Declination	+67° 14′ 08″[citation needed]
Apparent magnitude (V)	13.2[citation needed]
Characteristics
Spectral type	M2.5Ve / M3V[citation needed]
U−B color index	1.16[citation needed]
B−V color index	1.54[citation needed]
R−I color index	0.99[citation needed]
Variable type	Flare stars[citation needed]
Astrometry
A
Radial velocity (Rv)	10[citation needed] km/s
Proper motion (μ)	RA: 1739.0[citation needed] mas/yr Dec.: −224.93[citation needed] mas/yr
Parallax (π)	99.35±2.17 mas[4]
Distance	32.8 ± 0.7 ly (10.1 ± 0.2 pc)
Absolute magnitude (MV)	10.26[2]
B
Radial velocity (Rv)	−0.54±0.68[3] km/s
Proper motion (μ)	RA: 1703.226±0.035[3] mas/yr Dec.: −250.056±0.043[3] mas/yr
Parallax (π)	100.3966±0.0374 mas[3]
Distance	32.49 ± 0.01 ly (9.960 ± 0.004 pc)
Orbit[5]
Primary	Gliese 22 AC
Name	Gliese 22 B
Period (P)	223.3 yr
Semi-major axis (a)	3.322″
Eccentricity (e)	0.293
Inclination (i)	47.3°
Longitude of the node (Ω)	174.9°
Periastron epoch (T)	JD 1859.4
Argument of periastron (ω) (secondary)	146.3°
Orbit[6]
Primary	Gliese 22 A (Aa)
Name	Gliese 22 C (Ab)
Period (P)	5,694.2±14.9 days
Semi-major axis (a)	0.5106±0.0007″
Eccentricity (e)	0.163±0.002
Inclination (i)	43.7±0.2°
Longitude of the node (Ω)	178.3±0.2°
Periastron epoch (T)	JD 51817.2
Argument of periastron (ω) (secondary)	284.5±0.5°
Details[7]
Mass	0.378(A) + 0.136(C) M☉
Radius	0.5(A) R☉
Luminosity	0.04 L☉
Temperature	2000–3500 K
Details
B
Mass	0.382[8] M☉
Radius	0.394[8] R☉
Luminosity	0.011[9] L☉
Temperature	3,339[10] K
Metallicity [Fe/H]	−0.24[11] dex
Rotational velocity (v sin i)	<4[12] km/s
Other designations
2MASS J00322970+6714080, BD+66°34, CCDM J00325+6714, GJ 22, HIP 2552, LFT 47, V547 Cassiopeiae, ADS 440
Database references
SIMBAD	A
	B
Exoplanet Archive	data

Close

The discovery of flare activity on Gliese 22A was announced by Bjørn Ragnvald Pettersen in 1975,^[1] which led to it being given a variable star designation, V547 Cassiopeiae, in 1977.^[13]