Groombridge 34

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Groombridge 34 or ADS 246 A or Gliese 15 00h18m22.89s, +44°01'22.6"
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 18m 22.89s[1]
Declination +44° 01′ 22.6″[1]
Apparent magnitude (V) 8.09/11.06
Spectral type M1.5V + M3.5V
U−B color index 1.24
B−V color index 1.56
Variable type Flare stars
Radial velocity (Rv) +12.0 km/s
Proper motion (μ) RA: +2888.92 ± 0.60[1] mas/yr
Dec.: +410.10 ± 0.48[1] mas/yr
Parallax (π) 278.76 ± 0.77[1] mas
Distance 11.70 ± 0.03 ly
(3.587 ± 0.010 pc)
Absolute magnitude (MV) 10.32/13.29
Companion Groombridge 34 B
Gl 15 B
Period (P) 2,600 yr
Semi-major axis (a) 41.15"
Eccentricity (e) 0.00
Inclination (i) 61.4°
Longitude of the node (Ω) 45.3°
Periastron epoch (T) 1745
GX And
Mass 0.404[2] M
Radius 0.3863 ± 0.0021[3] R
Luminosity (bolometric) 0.02589[note 1] L
Luminosity (visual, LV) 0.00637[note 2] L
Surface gravity (log g) 4.89[2] cgs
Temperature 3,730 ± 49[2] K
Metallicity [Fe/H] -0.32 dex
GQ And
Mass 0.163 M
Radius 0.19 R
Luminosity (bolometric) ~0.00262[note 1] L
Luminosity (visual, LV) 0.00041[note 2] L
Temperature ~3,000 K
Other designations
GX/GQ Andromedae, BD +43°44, GCTP 49, GJ 15 A/B, Gl 171-047/171-048, HD 1326, HIP 1475, LHS 3/4, LTT 10108/10109, LFT 31/32, SAO 36248, Vys 085 A/B.
Database references
SIMBAD The system
A (GX And)
B (GQ And)
planet Ab
GJ 15 C (optical)

Groombridge 34 is a binary star system located about 11.7 light-years from the Sun. It consists of two red dwarfs in a nearly circular orbit with a separation of about 147 AU. Both stars in this pair exhibit variability due to random flares and they have been given variable star designations. (The brighter member Groombridge 34 A is designated GX And, and the other member is designated GQ And).

Planetary system[edit]

In August 2014, a planet orbiting around Groombridge 34 A was reported.[3] The planet's existence was deduced from analysis of the radial velocities of the parent Star by the Eta-Earth Survey using HIRES at Keck Observatory.

The planet is thought to have a minimum mass of 5.35 ± 0.75 Earth masses,[4] and at its discovery was the sixth nearest known exoplanet.

The Groombridge 34 A planetary system
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b ≥ 5.35±0.75 M 0.0717±0.0034 11.4433±0.0017 0.12?

See also[edit]


  1. ^ a b From \begin{smallmatrix}L=4 \pi R^2 \sigma T_{\rm eff}^4 \end{smallmatrix}, where \begin{smallmatrix}L \end{smallmatrix} is the luminosity, \begin{smallmatrix}R \end{smallmatrix} is the radius, \begin{smallmatrix}T_{\rm eff}\end{smallmatrix} is the effective surface temperature and \begin{smallmatrix}\sigma \end{smallmatrix} is the Stefan–Boltzmann constant
  2. ^ a b Using the absolute visual magnitude of Gliese 15 A, \scriptstyle M_{V_{\ast}}=10.32, and Gliese 15 B, \scriptstyle M_{V_{\ast}}=13.29, with the absolute visual magnitude of the Sun, \scriptstyle M_{V_{\odot}}=4.83, the two visual luminosities of the stars can be calculated by \scriptstyle \frac{L_{V_{\ast}}}{L_{V_{\odot}}}=10^{0.4\left(M_{V_{\odot}} - M_{V_{\ast}}\right)}


  1. ^ a b c d e van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c Berger, D. H.; et al. (2006). "First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars". The Astrophysical Journal 644 (1): 475–483. arXiv:astro-ph/0602105. Bibcode:2006ApJ...644..475B. doi:10.1086/503318. 
  3. ^ a b
  4. ^ Andrew Howard, Geoffrey Marcy, Debra A. Fischer, Howard Isaacson, Philip S. Muirhead, Gregory W. Henry, Tabetha S. Boyajian, Kaspar von Braun, Juliette C. Becker, Jason T. Wright, John Asher Johnson, Astrophysics Earth and Planetary Astrophysics : The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth.

External links[edit]


NAME Right ascension Declination Apparent magnitude (V) Spectral type Database references
ADS 246 B (ADS 246 AB) 00h 18m 24s +44° 01' 00 11.0 Simbad
ADS 246 C (V* GQ And) 00h 18m 25.868s +44° 01' 38.44 11.4 M3.5 Simbad
ADS 246 D (GJ 15 C) 00h 18m 00.13s +44° 00' 29.2 11.4 M5 Simbad