49 Librae

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[1] mas
Distance	95.3 ± 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
Mass	1.4[3] M☉
Radius	1.86+0.05; −0.04[1] R☉
Luminosity	4.74±0.03[1] L☉
Surface gravity (log g)	4.14[5] cgs
Temperature	6,237[4] K
Metallicity [Fe/H]	–0.02[4] dex
Rotational velocity (v sin i)	9.6±1.0[3] km/s
Age	12[6] Gyr
49 Lib B
Mass	0.45[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
SIMBAD	data

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

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.
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.
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, 46.
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.
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.
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.
"49 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-11-06.
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.
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.

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[GaiaDR2-1] 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.

[aaass34_1-2] 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.

[Willmarth2016-3] 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, 46.

[aaa475_2_519-4] 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.

[apj1_354_310-5] 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.

[Fuhrmann2017-6] 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.

[SIMBAD-7] "49 Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2013-11-06.

[apjs180_1_117-8] 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.

[Lazio2010-9] 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.