Groombridge 34
Ultraviolet band light curves for GX Andromedae, with flares marked by red arrows. Adapted from Pettersen and Griffin (1980) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Andromeda |
| Groombridge 34 A | |
| Right ascension | 00h 18m 22.88498s |
| Declination | +44° 01′ 22.6380″ |
| Apparent magnitude (V) | 8.119 |
| Groombridge 34 B | |
| Right ascension | 00h 18m 25.82514s |
| Declination | +44° 01′ 38.0924″ |
| Apparent magnitude (V) | 11.007 |
| Characteristics | |
| Spectral type | M1.4V + M4.1V |
| U−B color index | +1.24/+1.40 |
| B−V color index | +1.56/+1.80 |
| Variable type | Flare stars |
| Astrometry | |
| Groombridge 34 A | |
| Radial velocity (Rv) | +11.62±0.08 km/s |
| Proper motion (μ) | RA: 2,891.518 mas/yr Dec.: 411.832 mas/yr |
| Parallax (π) | 280.7068±0.0203 mas |
| Distance | 11.6191 ± 0.0008 ly (3.5624 ± 0.0003 pc) |
| Absolute magnitude (MV) | 10.32 |
| Groombridge 34 B | |
| Radial velocity (Rv) | 10.60±0.15 km/s |
| Proper motion (μ) | RA: 2,862.796 mas/yr Dec.: 336.432 mas/yr |
| Parallax (π) | 280.6947 ± 0.0278 mas |
| Distance | 11.620 ± 0.001 ly (3.5626 ± 0.0004 pc) |
| Absolute magnitude (MV) | 13.3 |
| Orbit | |
| Period (P) | 1,065±22 years |
| Semi-major axis (a) | 93+42 −6 AU |
| Eccentricity (e) | 0.73±0.01 |
| Inclination (i) | 36.7±0.7° |
| Longitude of the node (Ω) | 254.77±1.07° |
| Periastron epoch (T) | 2279±5 |
| Argument of periastron (ω) (secondary) | 324.7±1.6° |
| Details | |
| Groombridge 34 A | |
| Mass | 0.393+0.009 −0.008 M☉ |
| Radius | 0.385±0.002 R☉ |
| Luminosity | 0.02249±0.00019 L☉ |
| Habitable zone inner limit | 0.112 AU |
| Habitable zone outer limit | 0.239 AU |
| Surface gravity (log g) | 4.87±0.04 cgs |
| Temperature | 3,601+12 −11 K |
| Metallicity [Fe/H] | −0.34±0.09 dex |
| Rotation | 41.13±0.30 days |
| Rotational velocity (v sin i) | 1.09±0.79 km/s |
| Age | ~3.02 Gyr |
| Groombridge 34 B | |
| Mass | 0.15±0.02 M☉ |
| Radius | 0.18±0.03 R☉ |
| Luminosity | ~8.5×10−4 L☉ |
| Habitable zone inner limit | 0.048 AU |
| Habitable zone outer limit | 0.103 AU |
| Surface gravity (log g) | 5.08±0.15 cgs |
| Temperature | 3304±70 K |
| Metallicity [Fe/H] | −0.37±0.10 dex |
| Rotation | 108.20±1.72 days |
| Age | ~2.754 Gyr |
| Other designations | |
| GX/GQ Andromedae, BD+43° 44, GCTP 49, GJ 15 A/B, G 171-047/171-048, HD 1326, HIP 1475, LHS 3/4, LTT 10108/10109, SAO 36248, PPM 42798 | |
| Database references | |
| SIMBAD | GJ 15 A |
| GJ 15 Ab | |
| GJ 15 B | |
| Exoplanet Archive | data |
| ARICNS | GJ 15 A |
| GJ 15 B | |
Location of Groombridge 34 in the constellation Andromeda | |
Groombridge 34 is a binary star system in the northern constellation of Andromeda. It was listed as entry number 34 in A Catalogue of Circumpolar Stars, published posthumously in 1838 by British astronomer Stephen Groombridge. Based upon parallax measurements taken by the Gaia spacecraft, the system is located about 11.6 light-years (3.6 parsecs) from the Sun. This positions the pair among the nearest stars to the Solar System.
Both components are small, dim red dwarf stars that are too faint to be seen with the naked eye. They orbit around their common barycenter in a fairly eccentric orbit with a separation of about 93 AU and a period of around 1,065 years. Both stars exhibit random variation in luminosity due to flares and they have been given variable star designations: the brighter member Groombridge 34 A is designated GX And, while the smaller component is designated GQ And.
The star system has a relatively high proper motion of 2.9 arc seconds per year, and is moving away from the Solar System at a velocity of 11.6 km/s. It achieved perihelion some 15,000 years ago when it came within 11 ly (3.5 pc) of the Sun.