| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cassiopeia [2] |
| 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 [3] |
| Distance | 32.8 ± 0.7 ly (10.1 ± 0.2 pc) |
| Absolute magnitude (MV) | 10.26 [2] |
| Orbit [4] | |
| 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 [5] | |
| 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 [6] | |
| 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 [7] M☉ |
| Radius | 0.394 [7] R☉ |
| Luminosity | 0.011 [8] L☉ |
| Temperature | 3,339 [9] K |
| Metallicity [Fe/H] | −0.24 [10] dex |
| Rotational velocity (v sin i) | <4 [11] 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 |
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.
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. [12]
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. [13]
| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b(unconfirmed) | 16 MJ | — | 5,500 | 0 | — | — |