Astronomy:Gliese 251
Coordinates: 
06h 54m 48.96009s, +33° 16′ 05.4393″
  Gliese 251 Location of Gliese 251 in the constellation Gemini | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Gemini[1] |
| Right ascension | 06h 54m 48.95806s[2] |
| Declination | +33° 16′ 05.4383″[2] |
| Apparent magnitude (V) | +10.11[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | M3.0Ve[5] |
| U−B color index | +1.20[6] |
| B−V color index | +1.60[6] |
| Astrometry | |
| Radial velocity (Rv) | 22.30±0.19[2] km/s |
| Proper motion (μ) | RA: -726.672[2] mas/yr Dec.: -398.102[2] mas/yr |
| Parallax (π) | 179.0629 ± 0.0280[2] mas |
| Distance | 18.215 ± 0.003 ly (5.5846 ± 0.0009 pc) |
| Absolute magnitude (MV) | +11.12[1] |
| Details | |
| Mass | 0.360±0.015[4] M☉ |
| Radius | 0.364±0.011[4] R☉ |
| Luminosity | 0.0155±0.0004[7] L☉ |
| Surface gravity (log g) | 4.87±0.05[7] cgs |
| Temperature | 3342±24[7] K |
| Metallicity [Fe/H] | +0.07+0.07 −0.06[7] dex |
| Rotation | 122.1+1.9 −2.2 d[4] |
| Rotational velocity (v sin i) | ≤2[4] km/s |
| Age | 6.8+4.6 −4.7[7] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| ARICNS | data |
Gliese 251, also known as HIP 33226 or HD 265866, is a star located 18.2 light-years away from the Solar System. Located in the constellation of Gemini, it is the nearest star in this constellation.[9]: 84 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.[3] 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[5] with an effective temperature of about 3300 K.[5] Its mass has been measured to be around 0.36 solar masses[4] and its radius is about 36% solar radii.[4] Its metallicity is likely slightly less than that of the Sun.[11] Observations at infrared wavelengths rule out the presence of a circumstellar disk around it.[12]
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.[13] 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.[4] In 2025, a second planet (c) was confirmed which is also a super-Earth and orbits within the circumstellar habitable zone.[14] It may be possible to directly image planet c with next-generation telescopes such as the Thirty Meter Telescope.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥3.85+0.35 −0.33 M⊕ |
0.0808±0.0042 | 14.2370±0.0015 | 0 | — | — |
| c | ≥3.84±0.75 M⊕ | 0.196±0.014 | 53.647±0.044 | 0 | — | — |
See also
- List of exoplanets discovered in 2020 - Gliese 251 b
References
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 Høg, E. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. Bibcode: 2000A&A...355L..27H.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 Stock, S. et al. (2020). "The CARMENES search for exoplanets around M dwarfs. Three temperate-to-warm super-Earths". Astronomy & Astrophysics (EDP Sciences) 643: A112. doi:10.1051/0004-6361/202038820. ISSN 0004-6361. Bibcode: 2020A&A...643A.112S.
- ↑ 5.0 5.1 5.2 Lépine, Sébastien (2013). "A Spectroscopic Catalog of the Brightest (J < 9) M Dwarfs in the Northern Sky". The Astronomical Journal 145 (4): 102. doi:10.1088/0004-6256/145/4/102. Bibcode: 2013AJ....145..102L.
- ↑ 6.0 6.1 Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M.
- ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Beard, Corey et al. (October 2025). "Discovery of a Nearby Habitable Zone Super-Earth Candidate Amenable to Direct Imaging". The Astronomical Journal 170 (5): 279. doi:10.3847/1538-3881/ae0e20.
- ↑ "GJ 251". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=GJ+251.
- ↑ Kirkpatrick, J. Davy et al. (April 2024). "The Initial Mass Function Based on the Full-sky 20 pc Census of ~3600 Stars and Brown Dwarfs". The Astrophysical Journal Supplement Series 271 (2): 55. doi:10.3847/1538-4365/ad24e2. Bibcode: 2024ApJS..271...55K.
- ↑ "Stars within 15 light-years of Wolf 294". The Internet Stellar Database. http://www.stellar-database.com/Scripts/find_neighbors.exe?ID=44600&ly=15.
- ↑ Schweitzer, A.; Passegger, V. M.; Cifuentes, C.; Béjar, V. J. S.; Cortés-Contreras, M.; Caballero, J. A.; del Burgo, C.; Czesla, S. et al. (2019). "The CARMENES search for exoplanets around M dwarfs". Astronomy & Astrophysics (EDP Sciences) 625: A68. doi:10.1051/0004-6361/201834965. ISSN 0004-6361. Bibcode: 2019A&A...625A..68S.
- ↑ Beichman, C. A. (2006). "New Debris Disks around Nearby Main-Sequence Stars: Impact on the Direct Detection of Planets". The Astrophysical Journal 652 (2): 1674–1693. doi:10.1086/508449. Bibcode: 2006ApJ...652.1674B.
- ↑ Barnes, J. R.; et al. (2019-06-11). "Frequency of planets orbiting M dwarfs in the Solar neighbourhood". arXiv:1906.04644 [astro-ph.EP].
- ↑ "Super-Earth less than 20 light-years away is an exciting lead in the search for life". https://www.space.com/astronomy/exoplanets/super-earth-less-than-20-light-years-away-is-an-exciting-lead-in-the-search-for-life.
Notes
 |  |
