Gliese 849

Gliese 849, or GJ 849, is a small, solitary star in the equatorial constellation of Aquarius. It has a reddish hue and is invisible to the naked eye with an apparent visual magnitude of 10.41.[2] The distance to this star is 28.7 light years based on parallax,[1] but it is drifting closer to the Sun with a radial velocity of −15.3 km/s.[2] It has a pair of confirmed gas giant companions.[6]

Gliese 849
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Aquarius
Right ascension 22h 09m 40.34438s[1]
Declination –04° 38′ 26.6513″[1]
Apparent magnitude (V) 10.41[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type M3.5V[4]
U−B color index 1.055[2]
B−V color index 1.531±0.035[2]
V−R color index 1.12[2]
R−I color index 1.41[2]
Astrometry
Radial velocity (Rv)−15.26±0.10[2] km/s
Proper motion (μ) RA: 1,132.534±0.081[1] mas/yr
Dec.: −22.125±0.083[1] mas/yr
Parallax (π)113.4447 ± 0.0300 mas[5]
Distance28.750 ± 0.008 ly
(8.815 ± 0.002 pc)
Absolute magnitude (MV)10.62[2]
Details[4]
Mass0.4870±0.0048 M☉
Radius0.4833±0.0043 R☉
Luminosity0.02833±0.00045 L☉
Surface gravity (log g)4.771±0.032 cgs
Temperature3,601±19[6] K
Metallicity [Fe/H]0.35±0.10[6] dex
Rotation39.2±6.3 d[7]
Rotational velocity (v sin i)2.4[3] km/s
Other designations
BD−05°5715, GJ 849, HIP 109388, LFT 1689, LHS 517, LPM 814, LTT 8889, NLTT 53078, GCRV 13921, 2MASS J22094029-0438267[8]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata
Planet
Gliese 849bdata

The stellar classification of GJ 849 is M3.5V,[4] which means this is a small red dwarf star generating energy through hydrogen fusion at its core region. Various studies have found super-solar abundances in the spectra,[6] indicating that the elemental abundances of higher mass elements is significantly higher than in the Sun. The star has about half the mass and size of the Sun,[3] and is spinning slowly with a rotation period of approximately 39 days.[7] The estimated age of the star is more than three billion years.[3] It is radiating a mere 2.8%[4] of the luminosity of the Sun from its photosphere at an effective temperature of 3,601 K.[6]

Planetary system

In late 2006, a long-period Jupiter-like exoplanet was reported to be orbiting the red dwarf in a period just over 5 years in length. There was also a linear trend in the radial velocities which suggested another longer period companion.[3] The trend in the radial velocities was confirmed in 2013.[9] An orbit for the second exoplanet was finally determined in 2015. It is the first planet discovered orbiting a red dwarf with a semi-major axis greater than 0.21 AU.[6]

The Gliese 849 planetary system[6]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >0.911±0.036 MJ 2.39±0.082 1924±15 0.038±0.019 — —
c >0.944±0.070 MJ 4.82±0.21 5520±390 0.087±0.056 — —

See also

References
  1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. Butler, R. Paul; et al. (2006). "A Long-Period Jupiter-Mass Planet Orbiting the Nearby M Dwarf GJ 849". Publications of the Astronomical Society of the Pacific. 118 (850): 1685–1689. arXiv:astro-ph/0610179. Bibcode:2006PASP..118.1685B. doi:10.1086/510500. S2CID 14787596.
  4. 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.
  5. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. Gaia EDR3 record for this source at VizieR.
  6. Feng, Y. Katherina; et al. (2015). "The California Planet Survey IV: A Planet Orbiting the Giant Star HD 145934 and Updates to Seven Systems with Long-period Planets". The Astrophysical Journal. 800 (1). 22. arXiv:1501.00633. Bibcode:2015ApJ...800...22F. doi:10.1088/0004-637X/800/1/22. S2CID 56390823.
  7. Suárez Mascareño, A.; et al. (September 2015), "Rotation periods of late-type dwarf stars from time series high-resolution spectroscopy of chromospheric indicators", Monthly Notices of the Royal Astronomical Society, 452 (3): 2745–2756, arXiv:1506.08039, Bibcode:2015MNRAS.452.2745S, doi:10.1093/mnras/stv1441, S2CID 119181646.
  8. "BD-05 5715". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-20.
  9. Bonfils, Xavier; Delfosse, Xavier; Udry, Stéphane; Forveille, Thierry; Mayor, Michel; Perrier, Christian; Bouchy, François; Gillon, Michaël; Lovis, Christophe; Pepe, Francesco; Queloz, Didier; Santos, Nuno C.; Ségransan, Damien; Bertaux, Jean-Loup (2011). "The HARPS search for southern extra-solar planets XXXI. The M-dwarf sample". Astronomy and Astrophysics: A109. arXiv:1111.5019. Bibcode:2013A&A...549A.109B. doi:10.1051/0004-6361/201014704. S2CID 119288366.

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