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Gliese 849
Observation data; Epoch J2000.0 Equinox J2000.0
Constellation	Aquarius
Right ascension	22h 09m 40.34431s
Declination	–04° 38′ 26.6508″
Apparent magnitude (V)	10.41
Characteristics
Evolutionary stage	Main sequence
Spectral type	M3.5V
U−B color index	1.055
B−V color index	1.531±0.035
V−R color index	1.12
R−I color index	1.41
Astrometry
Radial velocity (Rv)	−15.26±0.10 km/s
Proper motion (μ)	RA: 1,132.583(39) mas/yr ; Dec.: −22.157(37) mas/yr
Parallax (π)	113.4447 ± 0.0300 mas
Distance	28.750 ± 0.008 ly ; (8.815 ± 0.002 pc)
Absolute magnitude (MV)	10.62
Details
Mass	0.465±0.011 M☉
Radius	0.464±0.018 R☉
Luminosity	0.02887±0.00025 L☉
Surface gravity (log g)	4.771±0.032 cgs
Temperature	3,467±68 K
Metallicity [Fe/H]	0.09±0.09 dex
Rotation	40.45+0.19; −0.18 d
Rotational velocity (v sin i)	2.4 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
Database references
SIMBAD	data
Exoplanet Archive	data
ARICNS	data
	Planet
Gliese 849b	data Archived 2019-06-05 at the Wayback Machine

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 28.8 light-years (8.8 parsecs) 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.^[8]

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,^[8] 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.^[9] The estimated age of the star is more than three billion years.^[3] It is radiating a mere 2.9%^[5] of the luminosity of the Sun from its photosphere at an effective temperature of 3,490 K.^[5]

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.^[10] An orbit for the second exoplanet was finally determined in 2015. The first planet discovered, Gliese 849 b, was the first planet discovered orbiting a red dwarf with a semi-major axis greater than 0.21 AU.^[8]

The Gliese 849 planetary system^[6]
Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	≥0.893+0.094 −0.097 $M$ _J	2.32+0.11 −0.13	1925.31±6.5	0.029±0.019	—	—
c	≥0.99±0.11 $M$ _J	4.95+0.25 −0.28	5990+110 −100	0.092+0.038 −0.036	—	—

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 ^c ^d ^e ^f ^g ^h ⁱ 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.
^ ^a ^b ^c ^d ^e 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.
^ ^a ^b 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.
^ ^a ^b ^c Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea. S2CID 235435757. 40.
^ ^a ^b ^c ^d Pinamonti, M.; Barbato, D.; et al. (June 2023). "The GAPS programme at TNG. XLVI. Deep search for low-mass planets in late-dwarf systems hosting cold Jupiters". Astronomy & Astrophysics. 677. arXiv:2306.04419. Bibcode:2023A&A...677A.122P. doi:10.1051/0004-6361/202346476. S2CID 259095781.
^ "BD-05 5715". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-02-20.
^ ^a ^b ^c 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.
^ 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.
^ 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. 549: A109. arXiv:1111.5019. Bibcode:2013A&A...549A.109B. doi:10.1051/0004-6361/201014704. S2CID 119288366.