37 Librae

37 Librae is a single^[8] 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	15h 34m 10.70209s[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 mas[1]
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	5.133±0.043[6] R☉
Luminosity	12.71±0.69[6] L☉
Surface gravity (log g)	3.19±0.06 cgs
Temperature	4,809±62[6] 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[7]
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.^[5] 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 12.7 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,809 K.^[6] At this temperature, 37 Librae glows with the hue of a K-type star.^[9]