Gliese 22, also catalogued V547 Cassiopeiae or ADS 440, is a hierarchical star system approximately 33 light-years 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.
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[2] |
Distance | 32.8 ± 0.7 ly (10.1 ± 0.2 pc) |
Absolute magnitude (MV) | 11.83 |
Orbit[3] | |
Primary | Gliese 22 AC |
Companion | 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[4] | |
Primary | Gliese 22 A (Aa) |
Companion | 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[5] | |
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[6] M☉ |
Radius | 0.394[6] R☉ |
Luminosity | 0.011[7] L☉ |
Temperature | 3,339[8] K |
Metallicity [Fe/H] | −0.24[9] dex |
Rotational velocity (v sin i) | <4[10] km/s |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
As of 2008, it was announced that a possible extrasolar planet, Gliese 22B b, orbits Gliese 22B but this is currently unconfirmed. The study in 2011 has indicated the orbit of the purported planet is stable.[11]
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b (unconfirmed) | 16 MJ | — | 5,500 | 0 | — | — |