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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	00 18 22.88498
Declination	+44° 01′ 22.6380″
Apparent magnitude (V)	8.119
Groombridge 34 B
Right ascension	00 18 25.82514
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)	1230+930 −110 yr
Semi-major axis (a)	93+42 −6 AU
Eccentricity (e)	0.53+0.23 −0.28
Inclination (i)	54+11 −16°
Longitude of the node (Ω)	2+35 −43°
Periastron epoch (T)	7140+560 −140
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	−0.34±0.09 dex
Rotation	43.86±0.56 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 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	−0.37±0.10 dex
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
ARICNS	GJ 15 A
	GJ 15 B
Groombridge 34Location 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 1,230 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.

GX Andromedae

The more massive and luminous component of the pair has the variable star designation GX Andromedae. It is a main-sequence red dwarf star of spectral type M1.4 that varies its brightness due to stellar flares. Gaia observations suggest a rotation period of 44 days and a magnetic activity cycle of roughly 9 years.

GQ Andromedae

The smaller companion bears the variable star name GQ Andromedae. It is a red dwarf main sequence star that undergoes flare events like the primary; it has a spectral type M4.1, so it also has a lower effective temperature.

Planetary system

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. At the time of its discovery, it was the sixth-nearest-known exoplanet.

Using the CARMENES spectrograph combined with the measurements of the HARPS 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.

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 3.03 M_E for Groombridge 34 Ab and 36 M_E 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 the Sun, hosting the longest-period Neptune-mass exoplanet discovered so far.

See also

• List of nearest stars and brown dwarfs

References

1. Pettersen, B. R.; Griffin, R. F. (December 1980). "Non-emission-line flare stars". The Observatory. 100: 198–202. Bibcode:1980Obs...100..198P. Retrieved 30 October 2022.
2. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
3. ^ 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, S2CID 19269312, 64.
4. ^ Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
5. ^ Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M.
6. ^ Nidever, David L.; et al. (August 2002), "Radial Velocities for 889 Late-Type Stars", The Astrophysical Journal Supplement Series, 141 (2): 503–522, arXiv:astro-ph/0112477, Bibcode:2002ApJS..141..503N, doi:10.1086/340570, S2CID 51814894.
7. ^ Pinamonti, M.; Damasso, M.; Marzari, F.; Sozzetti, A.; Desidera, S.; Maldonado, J.; Scandariato, G.; Affer, L.; Lanza, A. F.; Bignamini, A.; Bonomo, A. S.; Borsa, F.; Claudi, R.; Cosentino, R.; Giacobbe, P.; González-Álvarez, E.; González Hernández, J. I.; Gratton, R.; Leto, G.; Malavolta, L.; Martinez Fiorenzano, A.; Micela, G.; Molinari, E.; Pagano, I.; Pedani, M.; Perger, M.; Piotto, G.; Rebolo, R.; Ribas, I.; et al. (2018). "The HADES RV Programme with HARPS-N at TNG. VIII. GJ15A: A multiple wide planetary system sculpted by binary interaction". Astronomy and Astrophysics. 617: A104. arXiv:1804.03476. Bibcode:2018A&A...617A.104P. doi:10.1051/0004-6361/201732535. S2CID 54990041.
8. ^ Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea. S2CID 235435757. 40.
9. ^ Cantrell, Justin R.; et al. (October 2013), "The Solar Neighborhood XXIX: The Habitable Real Estate of Our Nearest Stellar Neighbors", The Astronomical Journal, 146 (4): 99, arXiv:1307.7038, Bibcode:2013AJ....146...99C, doi:10.1088/0004-6256/146/4/99, S2CID 44208180.
10. "V* GX And". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-02-09.{{cite web}}: CS1 maint: postscript (link)
11. Groombridge, Stephen (1838), Airy, George Biddell (ed.), A Catalogue of Circumpolar Stars, J. Murray, p. 2.
12. 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.
13. ^ Bailer-Jones, C. A. L. (March 2015). "Close encounters of the stellar kind". Astronomy & Astrophysics. 575: 13. arXiv:1412.3648. Bibcode:2015A&A...575A..35B. doi:10.1051/0004-6361/201425221. S2CID 59039482. A35.
14. Morris, Brett M.; Agol, Eric; Davenport, James R. A.; Hawley, Suzanne L. (2018). "Spotting stellar activity cycles in Gaia astrometry". Monthly Notices of the Royal Astronomical Society. 476 (4): 5408. arXiv:1802.09943. Bibcode:2018MNRAS.476.5408M. doi:10.1093/mnras/sty568. S2CID 73564680.
15. 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, S2CID 17361592, 51.
16. 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. S2CID 119340839.

External links

• SolStation entry
• Image Groombridge 34

v t e Constellation of Andromeda
Adhil Andromeda in Chinese astronomy List of Andromeda's satellite galaxies List of stars in Andromeda
Stars	Bayer α (Alpheratz) β (Mirach) γ (Almach) δ ε ζ η θ ι κ λ μ ν ξ (Adhil) ο π ρ σ τ υ (Titawin) φ χ ψ ω A b c υ Per (Nembus) Flamsteed 2 3 4 5 6 7 8 9 10 11 12 13 14 (Veritate) 15 18 22 23 26 28 32 36 39 41 44 45 47 55 56 58 59 63 64 65 66 6 Per Variable R T U W Z RT RV RX SU SW TU TW WZ XZ AB AC AD AE AF AR BM BX CC CG CN DS DX EG ET EU FF GO GP GQ GX GR GY HH HN IW KK KX KZ LL LN LP LQ OP OS OU PX PY QR QV QX V385 V428 V439 V455 V529 V807 HR 1 40 56 78 104 122 134 178 275 282 283 289 379 410 483 687 746 748 8884 8925 8950 8962 8973 9011 9074 9075 9105 HD 16175 (Buna) 222155 Other 3XMM J004232.1+411314 ADS 48 HAT-P-6 (Sterrennacht) HAT-P-16 HAT-P-19 HAT-P-28 M31-RV KELT-1 NGC 44 NGC 82 NGC 84 NGC 91 NGC 162 NGC 464 Qatar-3 Qatar-4 Qatar-5 PA-99-N2 WASP-1 WISE 0146+4234 WISE J0005+3737 WISE J004945.61+215120.0
Exoplanets 14 Andromedae b κ Andromedae b υ Andromedae b c d Gliese 15 Ab c HD 13931 b HD 16175 b HAT-P-6b HAT-P-32b WASP-1b WASP-33b Qatar-4b Qatar-5b
Star clusters	NGC 206 272 752 956 7686 Other Mayall II RBC EXT8
Nebulae	NGC 7662
Galaxies	Messier 32 110 NGC 5 11 13 19 20 21 27 39 43 48 49 51 67 68 69 70 71 72 74 76 79 80 81 83 85 86 90 93 94 96 97 108 109 112 140 149 160 169 181 183 184 214 218 226 228 229 233 243 252 258 260 262 280 304 317 389 393 404 425 431 477 512 513 523 528 529 531 536 542 561 605 620 668 679 687 700 703 704 705 708 709 710 712 714 717 721 732 753 759 801 812 834 891 906 910 911 912 913 920 937 980 995 996 999 1000 7640 7836 Numbered I II III IV V VIII IX X XI XVIII XIX XXI Other 3C 66A 3C 66B Andromeda Galaxy Arp 273 Donatiello I UGC 1840
Galaxy clusters Abell 262 NGC 68 group
Astronomical events GRB 101225A SN 1885A (S)
Category

• Andromeda (constellation)
• Flare stars
• M-type main-sequence stars
• Binary stars
• Henry Draper Catalogue objects
• Hipparcos objects
• Gliese and GJ objects
• Groombridge objects
• Durchmusterung objects
• Local Bubble
• Objects with variable star designations
• TIC objects
• Planetary systems with two confirmed planets