GJ 3512
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ursa Major
Right ascension 08h 41m 20.12866s[1]
Declination +59° 29′ 50.4441″[1]
Apparent magnitude (V) +15.05[2]
Characteristics
Evolutionary stage Main sequence
Spectral type dM5.5[3]
Astrometry
Radial velocity (Rv)+7.13±2.45[1] km/s
Proper motion (μ) RA: −260.276 mas/yr[1]
Dec.: −1,279.562 mas/yr[1]
Parallax (π)105.2935 ± 0.0313 mas[1]
Distance30.976 ± 0.009 ly
(9.497 ± 0.003 pc)
Details[3]
Mass0.1254±0.0031 M☉
Radius0.1636±0.0023 R☉
Luminosity0.001574±0.000018 L☉
Surface gravity (log g)5.240±0.044 cgs
Temperature3,081±51 K
Metallicity [Fe/H]−0.07±0.16 dex
Rotation87±5 d[4]
Rotational velocity (v sin i)2.0[5] km/s
Age3–8[6] Gyr
Other designations
G 234-45, LHS 252, LP 90-18, 2MASS J08412013+5929505[7]
Database references
SIMBADdata

GJ 3512 is a nearby star in the northern circumpolar constellation of Ursa Major. It is invisible to the naked eye but can be observed using a telescope, having an apparent visual magnitude of +15.05.[2] The star is located at a distance of 31 light-years from the Sun based on parallax.[1] It has a high proper motion,[6] traversing the celestial sphere at the rate of 1.311″ yr−1.[8] The measurement of the star's radial velocity is poorly constrained, but it appears to be drifting further away at a rate of ~8 km/s.[9]

The stellar classification of GJ 3512 is dM5.5,[3] which determines this to be a small red dwarf star that is generating energy through core hydrogen fusion. It displays a moderate amount of magnetic activity with a Sun-like cycle lasting 14 years. A low-level variability lasting ~87 d matches the approximate rotation period.[4] The star has 12.5% of the mass of the Sun and 16% of the Sun's radius. It is radiating 1.6% of the luminosity of the Sun from its photosphere at an effective temperature of 3,081 K.[3]

Planetary system

A gas giant planet in an eccentric orbit around GJ 3512 was discovered in 2019 utilizing the radial velocity method. The star's mass is only 250 times that of the gas giant, calling into question traditional models of planetary formation.[6][10] If the star was born in an open cluster, this planet may instead have formed around a higher-mass star then been swapped into this system during an interaction.[11] The eccentric orbit of this object may have been caused by the ejection of another exoplanet from the system.[6] A second gas giant planet on a wider, circular orbit is suspected;[6] a 2020 study provided stronger evidence for this planet,[4] and it is now considered confirmed by most sources.[12][13][14]

The GJ 3512 planetary system[4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥0.46+0.02
−0.01 MJ 		0.337±0.001 203.69+0.09
−0.02 		0.44±0.01 — —
c ≥0.20±0.01 MJ 1.292±0.003 1,599.6+1.1
−0.8 		0.0183±0.0001 — —

See also

References

  1. ^ a b c d e f 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.
  2. ^ a b Weis, Edward W. (1996). "Photometry of Stars with Large Proper Motion". The Astronomical Journal. 112: 2300. Bibcode:1996AJ....112.2300W. doi:10.1086/118183.
  3. ^ a b c d Schweitzer, A.; et al. (May 2019). "The CARMENES search for exoplanets around M dwarfs. Different roads to radii and masses of the target stars". Astronomy & Astrophysics. 625: 16. arXiv:1904.03231. Bibcode:2019A&A...625A..68S. doi:10.1051/0004-6361/201834965. S2CID 102351979. A68.
  4. ^ a b c d Lopez-Santiago, J.; et al. (2020). "A likely magnetic activity cycle for the exoplanet host M dwarf GJ 3512". The Astronomical Journal. 160 (6): 273. arXiv:2010.07715. Bibcode:2020AJ....160..273L. doi:10.3847/1538-3881/abc171. S2CID 222378457.
  5. ^ Reiners, Ansgar; et al. (2018). "The CARMENES search for exoplanets around M dwarfs. High-resolution optical and near-infrared spectroscopy of 324 survey stars". Astronomy and Astrophysics. 612: A49. arXiv:1711.06576. Bibcode:2018A&A...612A..49R. doi:10.1051/0004-6361/201732054. S2CID 62818673.
  6. ^ a b c d e Morales, J. C.; et al. (2019). "A giant exoplanet orbiting a very-low-mass star challenges planet formation models". Science. 365 (6460): 1441–1445. arXiv:1909.12174. Bibcode:2019Sci...365.1441M. doi:10.1126/science.aax3198. ISSN 0036-8075. PMID 31604272. S2CID 202888425.
  7. ^ "G 234-45". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-12-18.
  8. ^ Lépine, Sébastien; Shara, Michael M. (March 2005). "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)". The Astronomical Journal. 129 (3): 1483–1522. arXiv:astro-ph/0412070. Bibcode:2005AJ....129.1483L. doi:10.1086/427854. S2CID 2603568.
  9. ^ Newton, Elisabeth R.; et al. (2014). "Near-infrared Metallicities, Radial Velocities, and Spectral Types for 447 Nearby M Dwarfs". The Astronomical Journal. 147 (1): 20. arXiv:1310.1087. Bibcode:2014AJ....147...20N. doi:10.1088/0004-6256/147/1/20. S2CID 26818462.
  10. ^ Choi, Charles Q. (26 September 2019). "Surprise! Giant Planet Found Circling Tiny Red Dwarf Star". Space.com. Retrieved 26 September 2019.
  11. ^ Wang, Yi-Han; et al. (March 2020). "Giant Planet Swaps during Close Stellar Encounters". The Astrophysical Journal Letters. 891 (1): 6. arXiv:2002.08366. Bibcode:2020ApJ...891L..14W. doi:10.3847/2041-8213/ab77d0. S2CID 211204929. L14.
  12. ^ "Planet GJ 3512 c". Extrasolar Planets Encyclopaedia. 1995. Retrieved 28 August 2022.
  13. ^ "GJ 3512". NASA Exoplanet Archive. Retrieved 28 August 2022.
  14. ^ Reylé, Céline; Jardine, Kevin; Fouqué, Pascal; Caballero, Jose A.; Smart, Richard L.; Sozzetti, Alessandro (30 April 2021). "The 10 parsec sample in the Gaia era". Astronomy & Astrophysics. 650: A201. arXiv:2104.14972. Bibcode:2021A&A...650A.201R. doi:10.1051/0004-6361/202140985. S2CID 233476431. Data available at https://gruze.org/10pc/

External links

Constellation of Ursa Major
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