37 Librae

37 Librae is a single[7] star in the southern zodiac constellation of Libra. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.61.[2] The star is located 94 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +49 km/s.[5]

37 Librae

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Libra
Right ascension	15^h 34^m 10.70209^s[1]
Declination	−10° 03′ 52.3063″[1]
Apparent magnitude (V)	4.61[2]
Characteristics
Evolutionary stage	subgiant[3]
Spectral type	K1III–IV[4]
B−V color index	1.00±0.03[2]
Astrometry
Radial velocity (Rv)	+49.25±0.08[5] km/s
Proper motion (μ)	RA: +307.63[1] mas/yr Dec.: −234.51[1] mas/yr
Parallax (π)	34.57 ± 0.22[1] mas
Distance	94.3 ± 0.6 ly (28.9 ± 0.2 pc)
Absolute magnitude (MV)	2.30[2]
Details[5]
Mass	1.38±0.10 M☉
Radius	5.09±0.19 R☉
Luminosity	13.5+1.6 −1.5 L☉
Surface gravity (log g)	3.19±0.06 cgs
Temperature	4,836±22 K
Metallicity [Fe/H]	0.02±0.04 dex
Rotational velocity (v sin i)	2.02±0.33 km/s
Age	3.39±0.80 Gyr
Other designations
37 Lib, BD−09°4171, FK5 1409, GC 20914, HD 138716, HIP 76219, HR 5777, SAO 140609[6]
Database references
SIMBAD	data

This is an evolving subgiant star[3] with a stellar classification of K1 III–IV,[4] where the luminosity class indicates the spectrum displays blended traits of a subgiant and a giant star. It is an estimated 3.4 billion years old with 1.4 times the mass of the Sun. Having the supply of hydrogen at its core all but exhausted, the star is starting to expand; currently it has five times the girth of the Sun. It is radiating 13.5 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,836 K.[5]

References

1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
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.
3. Snowden, Michael S.; Young, Arthur (March 2005), "Radial Velocities of Late-Type Field Subgiant Stars", The Astrophysical Journal Supplement Series, 157 (1): 126–137, Bibcode:2005ApJS..157..126S, doi:10.1086/423711.
4. Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
5. Jofré, E.; et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics, 574: A50, arXiv:1410.6422, Bibcode:2015A&A...574A..50J, doi:10.1051/0004-6361/201424474, A50.
6. "37 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-17.
7. 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.