Both components are small, dimred dwarf stars that are too faint to be seen with the naked eye. They orbit around their commonbarycenter in a fairlyeccentric orbit with a separation of about 93AU and aperiod of around 1,065 years.[8][7] Both stars exhibit random variation in luminosity due toflares and they have been givenvariable star designations: the brighter member Groombridge 34 A is designatedGX And, while the smaller component is designatedGQ And.[14]
The star system has a relatively high proper motion of 2.9 arc seconds per year,[15] and is moving away from the Solar System at a velocity of 11.6 km/s.[6] It achievedperihelion some 15,000 years ago when it came within 11 ly (3.5 pc) of the Sun.[15]
The smaller companion bears the variable star nameGQ Andromedae. It is a red dwarf main sequence star that undergoes flare events like the primary; it has a spectral type M4.1,[3] so it also has a lowereffective temperature.
In August 2014, a planet orbiting around Groombridge 34 A was reported.[17] The planet's existence was deduced from analysis of theradial velocities of the parent star by the Eta-Earth Survey usingHIRES atKeck Observatory. At the time of its discovery, it was the sixth-nearest-knownexoplanet.
Using theCARMENES spectrograph combined with the measurements of theHARPS and HIRES spectrographs, researchers failed to detect the purported Groombridge 34 Ab. However, they did propose that another planet (Groombridge 34 Ac, GJ 15 Ac) could be orbiting the parent star.[18]
This discrepancy was later reconciled with new HIRES observations, covering a longer span of time, where both planets were recovered, constraining their minimum mass to 3.03M🜨 for Groombridge 34 Ab and 36M🜨 for Groombridge Ac. Their orbital periods are 11.4 and approximately 7,600 days, respectively. To date, this is the fourth-closest confirmed multi-planet system to theSun, hosting the longest-period Neptune-mass exoplanet discovered so far.[8]
^abKemmer, J.; Lafarga, M.; Fuhrmeister, B.; Shan, Y.; Schöfer, P.; Jeffers, S. V.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J. (2025-04-11), "The CARMENES search for exoplanets around M dwarfs. Cluster analysis of signals from spectral activity indicators to search for shared periods",Astronomy and Astrophysics,697,arXiv:2504.08363,Bibcode:2025A&A...697A.225K,doi:10.1051/0004-6361/202347056
^Petit, M. (October 1990), "Catalogue des étoiles variables ou suspectes dans le voisinage du Soleil",Astronomy and Astrophysics Supplement (in French),85 (2): 971,Bibcode:1990A&AS...85..971P.
^Trifonov, Trifon; Kürster, Martin; Zechmeister, Mathias; Tal-Or, Lev; Caballero, José A.; Quirrenbach, Andreas; Amado, Pedro J.; Ribas, Ignasi; Reiners, Ansgar; et al. (2018). "The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems".Astronomy and Astrophysics.609. A117.arXiv:1710.01595.Bibcode:2018A&A...609A.117T.doi:10.1051/0004-6361/201731442.S2CID119340839.
