Article · Wikipedia archive · Last revised Jun 12, 2026

37 Librae

37 Librae is a single 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. 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.

Last revised
Jun 12, 2026
Read time
≈ 2 min
Length
479 w
Citations
24
Source
37 Librae
Location of 37 Librae (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Libra
Right ascension 15h 34m 10.70209s1
Declination −10° 03′ 52.3063″1
Apparent magnitude (V) 4.612
Characteristics
Evolutionary stage subgiant3
Spectral type K1III–IV4
B−V color index 1.00±0.032
Astrometry
Radial velocity (Rv)+49.25±0.085 km/s
Proper motion (μ) RA: +307.631 mas/yr
Dec.: −234.511 mas/yr
Parallax (π)34.57±0.22 mas1
Distance94.3 ± 0.6 ly
(28.9 ± 0.2 pc)
Absolute magnitude (MV)2.302
Details5
Mass1.38±0.10 M
Radius5.133±0.0436 R
Luminosity12.71±0.696 L
Surface gravity (log g)3.19±0.06 cgs
Temperature4,809±626 K
Metallicity [Fe/H]0.02±0.04 dex
Rotational velocity (v sin i)2.02±0.33 km/s
Age3.39±0.80 Gyr
Other designations
37 Lib, BD−09°4171, FK5 1409, GC 20914, HD 138716, HIP 76219, HR 5777, SAO 1406097
Database references
SIMBADdata

37 Librae is a single8 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

This is an evolving subgiant star3 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

References

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, S2CID 18759600.
  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. 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, S2CID 53666931, A50.
  6. Rains, Adam D.; et al. (April 2020). "Precision angular diameters for 16 southern stars with VLTI/PIONIER". Monthly Notices of the Royal Astronomical Society. 493 (2): 2377–2394. arXiv:2004.02343. Bibcode:2020MNRAS.493.2377R. doi:10.1093/mnras/staa282.
  7. "37 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-17.
  8. 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.
  9. "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16