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Gliese 486 / Gar
	; Gliese 486 imaged by SDSS
Observation data; Epoch J2000 Equinox J2000
Constellation	Virgo
Right ascension	12h 47m 56.62457s
Declination	+09° 45′ 05.0357″
Apparent magnitude (V)	11.395
Characteristics
Evolutionary stage	main sequence
Spectral type	M3.5V
Astrometry
Radial velocity (Rv)	19.20±0.17 km/s
Proper motion (μ)	RA: −1008.267 mas/yr ; Dec.: −460.034 mas/yr
Parallax (π)	123.7756 ± 0.0329 mas
Distance	26.351 ± 0.007 ly ; (8.079 ± 0.002 pc)
Details
Mass	0.3120+0.0070; −0.0069 M☉
Radius	0.3243+0.0044; −0.0034 R☉
Luminosity	0.01151+0.00047; −0.00046 L☉
Surface gravity (log g)	4.9111+0.0068; −0.011 cgs
Temperature	3317+36; −37 K
Metallicity [Fe/H]	−0.15+0.13; −0.12 dex
Rotation	49.9±5.5 d
Rotational velocity (v sin i)	<2 km/s
Age	1-8 Gyr
Other designations
	Gar, GJ 486, HIP 62452, Wolf 437, TOI-1827, TYC 882-1111-1, 2MASS J12475664+0945050
Database references
SIMBAD	data

Gliese 486, also known as Wolf 437 and formally named Gar, is a red dwarf star 26.4 light-years (8.1 parsecs) away in the constellation Virgo. It hosts one known exoplanet.^[7]

Nomenclature

The designation Gliese 486 comes from the Gliese Catalogue of Nearby Stars. This was the 486th star listed in the first edition of the catalogue.

In August 2022, this planetary system was included among 20 systems to be named by the third NameExoWorlds project.^[8] The approved names, proposed by a team from Spain, were announced in June 2023. Gliese 486 is named Gar and its planet is named Su, after the Basque words for "flame" and "fire".^[9]

Properties

Gliese 486 has a surface temperature of 3340±54 K. Gliese 486 is similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of 0.07±0.16. It was suspected to be a flare star,^[10] although measurements available in 2019 did not reveal any flares.^[11] The chemical makeup of the star is unremarkable and consistent with solar abundances or being slightly metal-poor.^[5]

The star has an unremarkable magnetic field in the chromosphere of about 1.6 kilogauss.^[6] It is rotating very slowly and is likely to be very old, belonging kinematically to the old thin disk of the Milky Way.^[12]

Multiplicity surveys did not detect any stellar companions to Gliese 486 as of 2020.^[13]

Planetary system

Artist's impression and size comparison of Gliese 486b and Earth. In reality, the exoplanet likely has little to no atmosphere.

In 2021, one planet, named Gliese 486 b, was discovered on a tight, circular orbit.^[7] It represents a rare class of rocky exoplanet suitable for spectroscopic characterization in the near future^[14] by the James Webb Space Telescope.^[15] By 2022, no hydrogen or steam dominated atmosphere was detected, although a secondary planetary atmosphere with a higher molecular weight remained a possibility.^[16] Observations by JWST announced in 2023 detected signs of water vapor, but it was unclear if this is from the planet's atmosphere or from its host star.^[17]^[18]

Secondary eclipse observations by JWST published in 2024 show a planetary dayside temperature of 865±14 K (592 °C; 1,097 °F). This is consistent with a lack of heat redistribution, indicating that the planet likely has little to no atmosphere and the previous water vapor detection was likely a result of contamination from the host star. Gliese 486 b is thus similar to other hot rocky planets around red dwarfs, such as LHS 3844 b, GJ 1252 b, TRAPPIST-1b, and GJ 1132 b.^[4]

The Gliese 486 planetary system^[4]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b / Su	2.770+0.076 −0.073 $M$ _🜨	0.01714±0.00013	1.46712127+0.00000031 −0.00000035	0.00086+0.0016 −0.00043	89.39+0.41 −0.42°	1.289+0.019 −0.014 $R$ _🜨

References

^ ^a ^b ^c ^d ^e 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.
^ ^a ^b "Wolf 437". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-03-10.
^ Bozhinova, I.; Helling, Ch.; Scholz, A. (2014), "Planetary host stars: Evaluating uncertainties in cool model atmospheres", Monthly Notices of the Royal Astronomical Society, 450 (1): 160–182, arXiv:1405.5416, Bibcode:2015MNRAS.450..160B, doi:10.1093/mnras/stv613
^ ^a ^b ^c Mansfield, Megan Weiner; Xue, Qiao; Zhang, Michael; Mahajan, Alexandra S.; Ih, Jegug; Koll, Daniel; Bean, Jacob L.; Coy, Brandon Park; Eastman, Jason D.; Kempton, Eliza M.-R.; Kite, Edwin S.; Lunine, Jonathan (2024). "No Thick Atmosphere on the Terrestrial Exoplanet GI 486b". arXiv:2408.15123.
^ ^a ^b ^c Caballero, J. A.; et al. (2022), "A detailed analysis of the Gl 486 planetary system", Astronomy & Astrophysics, 665: A120, arXiv:2206.09990, Bibcode:2022A&A...665A.120C, doi:10.1051/0004-6361/202243548, S2CID 249889232
^ ^a ^b Moutou, Claire; Hébrard, Élodie M.; Morin, Julien; Malo, Lison; Fouqué, Pascal; Torres-Rivas, Andoni; Martioli, Eder; Delfosse, Xavier; Artigau, Étienne; Doyon, René (2017), "SPIRou input catalogue: Activity, rotation and magnetic field of cool dwarfs", Monthly Notices of the Royal Astronomical Society, 472 (4): 4563–4586, arXiv:1709.01650, Bibcode:2017MNRAS.472.4563M, doi:10.1093/mnras/stx2306
^ ^a ^b Trifonov, T.; et al. (2021), "A nearby transiting rocky exoplanet that is suitable for atmospheric investigation", Science, 371 (6533): 1038–1041, arXiv:2103.04950, Bibcode:2021Sci...371.1038T, doi:10.1126/science.abd7645, PMID 33674491, S2CID 232124642
^ "List of ExoWorlds 2022". nameexoworlds.iau.org. IAU. 8 August 2022. Archived from the original on 8 March 2023. Retrieved 27 August 2022.
^ "2022 Approved Names". nameexoworlds.iau.org. IAU. Archived from the original on 1 May 2024. Retrieved 7 June 2023.
^ O'Donoghue, D.; Koen, C.; Kilkenny, D.; Stobie, R. S.; Koester, D.; Bessell, M. S.; Hambly, N.; MacGillivray, H. (2003), "The DA+d Me eclipsing binary EC13471-1258: its cup runneth over ... Just", Monthly Notices of the Royal Astronomical Society, 345 (2): 506–528, arXiv:astro-ph/0307144, Bibcode:2003MNRAS.345..506O, doi:10.1046/j.1365-8711.2003.06973.x, S2CID 17408072
^ Vida, Krisztián; Leitzinger, Martin; Kriskovics, Levente; Seli, Bálint; Odert, Petra; Kovács, Orsolya Eszter; Korhonen, Heidi; Van Driel-Gesztelyi, Lidia (2019), "The quest for stellar coronal mass ejections in late-type stars", Astronomy & Astrophysics, 623: A49, arXiv:1901.04229, doi:10.1051/0004-6361/201834264, S2CID 119095055
^ Browning, Matthew K.; Basri, Gibor; Marcy, Geoffrey W.; West, Andrew A.; Zhang, Jiahao (2010), "Rotation and Magnetic Activity in a Sample of M-Dwarfs", The Astronomical Journal, 139 (2): 504, Bibcode:2010AJ....139..504B, doi:10.1088/0004-6256/139/2/504, S2CID 121835145
^ Lamman, Claire; Baranec, Christoph; Berta-Thompson, Zachory K.; Law, Nicholas M.; Schonhut-Stasik, Jessica; Ziegler, Carl; Salama, Maïssa; Jensen-Clem, Rebecca; Duev, Dmitry A.; Riddle, Reed; Kulkarni, Shrinivas R.; Winters, Jennifer G.; Irwin, Jonathan M. (2020), "Robo-AO M-dwarf Multiplicity Survey: Catalog", The Astronomical Journal, 159 (4): 139, arXiv:2001.05988, Bibcode:2020AJ....159..139L, doi:10.3847/1538-3881/ab6ef1, S2CID 210718832
^ "Hot Super-Earth Discovered 26 Light-Years Away". Archived from the original on 2021-12-09. Retrieved 2021-03-10.
^ "Newfound exoplanet could be 'Rosetta Stone' for studies of alien atmospheres". Space.com. 4 March 2021. Archived from the original on 2023-03-30. Retrieved 2021-03-10.
^ Ridden-Harper, Andrew; Nugroho, Stevanus; Flagg, Laura; Jayawardhana, Ray; Turner, Jake D.; Ernst de Mooij; MacDonald, Ryan; Deibert, Emily; Tamura, Motohide; Kotani, Takayuki; Hirano, Teruyuki; Kuzuhara, Masayuki; Omiya, Masashi; Kusakabe, Nobuhiko (2023), "High-resolution Transmission Spectroscopy of the Terrestrial Exoplanet GJ 486b", The Astronomical Journal, 165 (4): 170, arXiv:2212.11816, Bibcode:2023AJ....165..170R, doi:10.3847/1538-3881/acbd39
^ Moran, Sarah E.; Stevenson, Kevin B.; et al. (May 2023). "High Tide or Rip-Tide on the Cosmic Shoreline? A Water-Rich Atmosphere or Stellar Contamination for the Warm Super-Earth GJ 486b from JWST Observations". The Astrophysical Journal Letters. 948 (1): L11. arXiv:2305.00868. Bibcode:2023ApJ...948L..11M. doi:10.3847/2041-8213/accb9c.
^ "Webb Finds Water Vapor, But From a Rocky Planet or Its Star?". webbtelescope.org. STScI. 1 May 2023. Archived from the original on 2 May 2023. Retrieved 1 May 2023.