Astronomy:37 Librae

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Short description: Star in the constellation Libra
37 Librae
Observation data
Equinox J2000.0]] (ICRS)
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[1] mas
Distance94.3 ± 0.6 ly
(28.9 ± 0.2 pc)
Absolute magnitude (MV)2.30[2]
Details[5]
Mass1.38±0.10 M
Radius5.133±0.043[6] R
Luminosity12.71±0.69[6] L
Surface gravity (log g)3.19±0.06 cgs
Temperature4,809±62[6] 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 140609[7]
Database references
SIMBADdata

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]

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]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 Snowden, Michael S.; Young, Arthur (March 2005), "Radial Velocities of Late-Type Field Subgiant Stars", The Astrophysical Journal Supplement Series 157 (1): 126–137, doi:10.1086/423711, Bibcode2005ApJS..157..126S. 
  4. 4.0 4.1 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series 71: 245, doi:10.1086/191373, Bibcode1989ApJS...71..245K. 
  5. 5.0 5.1 5.2 5.3 Jofré, E. et al. (2015), "Stellar parameters and chemical abundances of 223 evolved stars with and without planets", Astronomy & Astrophysics 574: A50, doi:10.1051/0004-6361/201424474, A50, Bibcode2015A&A...574A..50J. 
  6. 6.0 6.1 6.2 6.3 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. doi:10.1093/mnras/staa282. Bibcode2020MNRAS.493.2377R. 
  7. "37 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=37+Lib. 
  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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  9. "The Colour of Stars", Australia Telescope, Outreach and Education (Commonwealth Scientific and Industrial Research Organisation), December 21, 2004, http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html, retrieved 2012-01-16