49 Librae
Observation data
Epoch J2000      Equinox J2000
Constellation Libra
Right ascension 16h 00m 19.61087s[1]
Declination –16° 32′ 00.5483″[1]
Apparent magnitude (V) 5.47[2]
Characteristics
Evolutionary stage main sequence
Spectral type F8 V[3]
U−B color index +0.03[2]
B−V color index +0.52[2]
Astrometry
Radial velocity (Rv)−20.1±4.0[4] km/s
Proper motion (μ) RA: –644.387[1] mas/yr
Dec.: –360.803[1] mas/yr
Parallax (π)34.2281 ± 0.1906 mas[1]
Distance95.3 ± 0.5 ly
(29.2 ± 0.2 pc)
Absolute magnitude (MV)2.89[4]
Orbit[3]
Period (P)1,142.4±1.1 d
Semi-major axis (a)≥ 59.53±0.244 Gm
Eccentricity (e)0.110±0.012
Inclination (i)143.0±2.0°
Longitude of the node (Ω)163.5±2.8°
Periastron epoch (T)57025±22 MJD
Argument of periastron (ω)
(secondary)		69.4±7.4°
Semi-amplitude (K1)
(primary)		3.847±0.051 km/s
Details
49 Lib A
Mass1.4[3] M☉
Radius1.86+0.05
−0.04[1] R☉
Luminosity4.74±0.03[1] L☉
Surface gravity (log g)4.14[5] cgs
Temperature6,237[4] K
Metallicity [Fe/H]–0.02[4] dex
Rotational velocity (v sin i)9.6±1.0[3] km/s
Age12[6] Gyr
49 Lib B
Mass0.45[3] M☉
Other designations
49 Lib, BD–16°4196, FK5 1419, GJ 3931, HD 143333, HIP 78400, HR 5954, SAO 159625, WDS J16003-1632A[7]
Database references
SIMBADdata

49 Librae is the Flamsteed designation for a binary star[8] system in the Zodiac constellation of Libra. It has an apparent visual magnitude of 5.47,[2] making it faintly visible to the naked eye from dark suburban skies as a dim, yellow-white hued star. The system is located 95 light years away from the Sun, based on parallax,[1] but is drifting closer with a radial velocity of −20 km/s.[4]

The variable nature of the velocity for 49 Librae was first noted by W. S. Adams in 1924. It is a single-lined spectroscopic binary with an orbital period of 3.128 years and an eccentricity of 0.11.[3] The primary component has a stellar classification of F8 V or F9 V,[3] indicating it is an F-type main-sequence star. It has an estimated 1.4 times the mass of the Sun, while the companion only has 0.4 solar masses.[3] The system is a source for radio and X-ray emissions, which may be coming from the secondary companion.[9]

References

  1. 1 2 3 4 5 6 7 8 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.
  2. 1 2 3 4 Nicolet, B. (October 1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
  3. 1 2 3 4 5 6 7 8 Willmarth, Daryl W.; et al. (August 2016), "Spectroscopic Orbits for 15 Late-type Stars" (PDF), The Astronomical Journal, 152 (2): 13, Bibcode:2016AJ....152...46W, doi:10.3847/0004-6256/152/2/46, S2CID 53648490, 46.
  4. 1 2 3 4 5 Nordström, B.; et al. (November 2007), "The Geneva-Copenhagen survey of the Solar neighbourhood. II. New uvby calibrations and rediscussion of stellar ages, the G dwarf problem, age-metallicity diagram, and heating mechanisms of the disk", Astronomy & Astrophysics, 475 (2): 519–537, arXiv:0707.1891, Bibcode:2007A&A...475..519H, doi:10.1051/0004-6361:20077221, S2CID 119054949.
  5. ↑ Balachandran, Suchitra (May 1, 1990), "Lithium depletion and rotation in main-sequence stars", Astrophysical Journal, Part 1, 354: 310–332, Bibcode:1990ApJ...354..310B, doi:10.1086/168691.
  6. ↑ Fuhrmann, K.; Chini, R. (January 2, 2017), "Bright Times for an Ancient Star", The Astrophysical Journal, 834 (2): 114, Bibcode:2017ApJ...834..114F, doi:10.3847/1538-4357/834/2/114, S2CID 125888005.
  7. ↑ "49 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-11-06.
  8. ↑ Abt, Helmut A. (January 2009), "MK Classifications of Spectroscopic Binaries", The Astrophysical Journal Supplement, 180 (1): 117–118, Bibcode:2009ApJS..180..117A, doi:10.1088/0067-0049/180/1/117, S2CID 122811461.
  9. ↑ Lazio, T. Joseph W.; et al. (January 2010), "A Blind Search for Magnetospheric Emissions from Planetary Companions to Nearby Solar-Type Stars", The Astronomical Journal, 139 (1): 96–101, arXiv:0910.3938, Bibcode:2010AJ....139...96L, doi:10.1088/0004-6256/139/1/96, S2CID 118537554.
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