Gliese 251


Gliese 251
Observation data
Epoch J2000      Equinox J2000
Constellation Gemini
Right ascension 06h 54m 48.96009s[1]
Declination +33° 16′ 05.4393″[1]
Apparent magnitude (V) +10.11[2]
Spectral type M3.0Ve[3]
U−B color index +1.20[4]
B−V color index +1.60[4]
Radial velocity (Rv)22.91[5] km/s
Proper motion (μ) RA: -723.99[1] mas/yr
Dec.: -398.40[1] mas/yr
Parallax (π)179.16 ± 0.06[6] mas
Distance18.205 ± 0.006 ly
(5.582 ± 0.002 pc)
Absolute magnitude (MV)11.23[7]
Mass0.360±0.015[6] M
Radius0.364±0.011[6] R
Surface gravity (log g)4.96±0.07[6] cgs
Temperature3451±51[6] K
Metallicity [Fe/H]-0.03±0.16[6] dex
Rotational velocity (v sin i)≤2[6] km/s
Other designations
Gliese 251, HD 265866, HIP 33226, LHS 1879, LTT 11941, Ross 578, Wolf 294, 2MASS J06544902+3316058[8]
Database references

Gliese 251, also known as HIP 33226 or HD 265866, is a star located about 18 light years away from the Solar System. Located in the constellation of Gemini, it is the nearest star in this constellation.[9] It is located near the boundary with Auriga, 49 arcminutes away from the bright star Theta Geminorum; due to its apparent magnitude of +9.89 it cannot be observed with the naked eye.[2] The closest star to Gliese 251 is QY Aurigae, which is located 3.5 light years away.[10]

Gliese 251 is a red dwarf with a spectral type of M3V[3] with an effective temperature of about 3300 K.[3] Its mass has been measured to be around 0.36 solar masses[6] and its radius is about 36% solar radii.[6] Its metallicity is likely slightly less than that of the Sun.[6] Observations at infrared wavelengths rule out the presence of a circumstellar disk around it.[11]

Planetary system

In 2019, two candidate planets were detected by the radial velocity method to orbit Gliese 251 at orbits of 1.74 and 607 days.[12] However, a new study in 2020 using CARMENES data refuted both candidates, as they found that both signals were caused by stellar activity. Based on the CARMENES data, the team announced that Gliese 251 is orbited by one single super-Earth (Gliese 251 b) at an orbit of 14.238 days.[6]

The Gliese 251 planetary system[6]
(in order from star)
Mass Semimajor axis
Orbital period
Eccentricity Inclination Radius
b ≥4.0±0.4 M 0.0818+0.0011
14.238±0.002 0.10+0.09


  1. ^ a b c d van Leeuwen, F.; et al. (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. S2CID 18759600.
  2. ^ a b Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  3. ^ a b c Lépine, Sébastien (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal. 145 (4): 102. arXiv:1206.5991. Bibcode:2013AJ....145..102L. doi:10.1088/0004-6256/145/4/102. S2CID 117144290.
  4. ^ a b Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
  5. ^ Nidever, David L.; et al. (2013). "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.
  6. ^ a b c d e f g h i j k l Stock, S.; et al. (2020), "The CARMENES search for exoplanets around M dwarfs Three temperate-to-warm super-Earths", Astronomy & Astrophysics, A112: 643, arXiv:2010.00474, Bibcode:2020A&A...643A.112S, doi:10.1051/0004-6361/202038820, S2CID 222090233
  7. ^ "ARICNS 4C00526". ARICNS. Retrieved 8 February 2017.
  8. ^ "GJ 251". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 8 February 2017.
  9. ^ "Closest Stars". Retrieved 8 February 2017.
  10. ^ "Stars within 15 light-years of Wolf 294". The Internet Stellar Database. Retrieved 7 February 2017.
  11. ^ Beichman, C. A.; et al. (2006). "New Debris Disks around Nearby Main-Sequence Stars: Impact on the Direct Detection of Planets". The Astrophysical Journal. 652 (2): 1674–1693. arXiv:astro-ph/0611682. Bibcode:2006ApJ...652.1674B. doi:10.1086/508449. S2CID 14207148.
  12. ^ Barnes, J. R.; et al. (2019-06-11). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv:1906.04644 [astro-ph.EP].