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) | 10.26 |
| Orbit | |
| 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 | |
| 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 | |
| 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 M☉ |
| Radius | 0.394 R☉ |
| Luminosity | 0.011 L☉ |
| Temperature | 3,339 K |
| Metallicity [Fe/H] | −0.24 dex |
| Rotational velocity (v sin i) | <4 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, which led to it being given a variable star designation, V547 Cassiopeiae, in 1977.