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31 Boötis
Observation data; Epoch J2000 Equinox J2000
Constellation	Boötes
Right ascension	14h 41m 38.75049s
Declination	+08° 09′ 42.3409″
Apparent magnitude (V)	4.86
Characteristics
Spectral type	G7 IIIa
B−V color index	0.992±0.038
Astrometry
Radial velocity (Rv)	−16.5±1.8 km/s
Proper motion (μ)	RA: –9.589 mas/yr ; Dec.: +3.906 mas/yr
Parallax (π)	6.8757 ± 0.2796 mas
Distance	470 ± 20 ly ; (145 ± 6 pc)
Absolute magnitude (MV)	−1.22
Details
Mass	3.27 M☉
Radius	23.25+0.40; −0.49 R☉
Luminosity	274.9±12.6 L☉
Surface gravity (log g)	2.60 cgs
Temperature	4,874+53; −41 K
Metallicity [Fe/H]	−0.10 dex
Rotational velocity (v sin i)	6.5 km/s
Age	370 Myr
Other designations
	31 Boo, NSV 6769, BD+08°2903, FK5 3163, GC 19789, HD 129312, HIP 71832, HR 5480, SAO 120601
Database references
SIMBAD	data

31 Boötis is a single^[8] star in the northern constellation of Boötes,^[7] located 470 light years from the Sun.^[1] It is visible to the naked eye as a faint, yellow-hued star with an apparent visual magnitude of 4.86.^[2] The object is moving closer to the Earth with a heliocentric radial velocity of −16.5 km/s.^[2] It was known to be part of a constellation between Virgo and Boötes named Mons Maenalus, it was also the brightest star in the constellation.

This is an evolved giant star with a stellar classification of G7 IIIa.^[3] It is a suspected variable star of unknown type,^[9] and is an X-ray source.^[10] The star is 370^[4] million years old with 3.27^[4] times the mass of the Sun. Having exhausted the hydrogen at its core, the star has expanded to 23^[1] times the Sun's radius. It is radiating 275^[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,874 K.^[1]

References

^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l 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.
^ ^a ^b ^c ^d ^e ^f 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 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins Catalog of Revised MK Types for the Cooler Stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
^ ^a ^b ^c ^d Luck, R. Earle (2015), "Abundances in the Local Region. I. G and K Giants", Astronomical Journal, 150 (3), 88, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114.
^ ^a ^b Hekker, S.; Meléndez, J. (2007), "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters", Astronomy and Astrophysics, 475 (3): 1003, arXiv:0709.1145, Bibcode:2007A&A...475.1003H, doi:10.1051/0004-6361:20078233, S2CID 10436552.
^ De Medeiros, J. R.; et al. (November 2000), "Rotation and lithium in single giant stars", Astronomy and Astrophysics, 363: 239–243, arXiv:astro-ph/0010273, Bibcode:2000A&A...363..239D.
^ ^a ^b "31 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved May 10, 2019.
^ Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
^ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
^ Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138, S2CID 119267456.