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Epoch J2000 Equinox J2000
|Right ascension||00h 18m 22.89s|
|Declination||+44° 01′ 22.6″|
|Apparent magnitude (V)||8.119/11.007|
|Spectral type||M1.4V + M4.1V|
|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 mas/yr
Dec.: +410.10 ± 0.48 mas/yr
|Parallax (π)||278.76 ± 0.77 mas|
|Distance||11.70 ± 0.03 ly
(3.587 ± 0.010 pc)
|Companion||Groombridge 34 B
Gl 15 B
|Period (P)||2,600 yr|
|Semi-major axis (a)||41.15"|
|Longitude of the node (Ω)||45.3°|
|Periastron epoch (T)||1745|
|Radius||0.3863 ± 0.0021 R☉|
|Luminosity (bolometric)||0.02589[note 1] L☉|
|Luminosity (visual, LV)||0.00637[note 2] L☉|
|Surface gravity (log g)||4.89 cgs|
|Temperature||3,730 ± 49 K|
|Metallicity [Fe/H]||-0.32 dex|
|Luminosity (bolometric)||~0.00262[note 1] L☉|
|Luminosity (visual, LV)||0.00041[note 2] L☉|
|Metallicity [Fe/H]||−0.30 dex|
Groombridge 34 is a binary star system in the northern constellation of Andromeda. Based upon parallax measurements taken by the Hipparcos spacecraft, they are located about 11.7 light-years from the Sun. Both components are small, faint red dwarf stars that are too faint to be seen with the naked eye. They orbit around their common barycenter in a nearly circular orbit with a separation of about 147 AU. 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, and the other member is designated GQ And.
In August 2014, a planet orbiting around Groombridge 34 A was reported. 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.
(in order from star)
|b||≥ 5.35±0.75 M⊕||0.0717±0.0034||11.4433±0.0017||0.12?||—||—|
- From , where is the luminosity, is the radius, is the effective surface temperature and is the Stefan–Boltzmann constant
- Using the absolute visual magnitude of Gliese 15 A, , and Gliese 15 B, , with the absolute visual magnitude of the Sun, , the two visual luminosities of the stars can be calculated by
- 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
- Mann, Andrew W.; et al. (May 2015), "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius", The Astrophysical Journal 804 (1): 38, arXiv:1501.01635, Bibcode:2015ApJ...804...64M, doi:10.1088/0004-637X/804/1/64, 64.
- 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.
- Howard, Andrew W.; et al. (October 2014), "The NASA-UC-UH ETA-Earth Program. IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth", The Astrophysical Journal 794 (1): 9, arXiv:1408.5645, Bibcode:2014ApJ...794...51H, doi:10.1088/0004-637X/794/1/51, 51.
- "V* GX And -- Flare Star", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), retrieved 2016-02-09.
- Howard, Andrew; et al., "The NASA-UC-UH Eta-Earth Program: IV. A Low-mass Planet Orbiting an M Dwarf 3.6 PC from Earth", Astrophysics Earth and Planetary Astrophysics, arXiv:1408.5645.
- SolStation entry
- Image Groombridge 34
- The One Hundred Nearest Star Systems, RECONS
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