Astronomy:Lambda Librae

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Short description: Binary star system in the constellation Libra
Lambda Librae
Observation data
Equinox J2000.0]] (ICRS)
Constellation Libra
Right ascension  15h 53m 20.05463s[1]
Declination −20° 10′ 01.4177″[1]
Apparent magnitude (V) 5.03[2]
Characteristics
Spectral type B3 V[3]
U−B color index −0.584[2]
B−V color index −0.023[2]
Variable type Rotating ellipsoidal[4]
Astrometry
Radial velocity (Rv)−2.0±0.5[5] km/s
Proper motion (μ) RA: −9.81[1] mas/yr
Dec.: −26.85[1] mas/yr
Parallax (π)10.54 ± 0.91[1] mas
Distance310 ± 30 ly
(95 ± 8 pc)
Absolute magnitude (MV)0.56[6]
Orbit[7]
Period (P)14.4829±0.0004 d
Eccentricity (e)0.27±0.09
Periastron epoch (T)2435172.380 ± 0.664 JD
Argument of periastron (ω)
(secondary)		217±17°
Semi-amplitude (K1)
(primary)		28.5±3.3 km/s
Details
Mass5.01±0.26[8] M☉
Radius3.9[9] R☉
Luminosity743[8] L☉
Surface gravity (log g)4.75 cgs
Temperature18,700[8] K
Metallicity [Fe/H]−0.27 dex
Rotational velocity (v sin i)155[10] km/s
Age282[6] Myr
Other designations
λ Lib, 45 Lib, BD−19°4249, FK5 1415, HD 142096, HIP 77811, HR 5902, SAO 183895.[11]
Database references
SIMBADdata

λ Librae (Latinised as Lambda Librae) is the Bayer designation for a binary star system in the zodiac constellation of Libra. It can be faintly seen with the naked eye, having an apparent visual magnitude of 5.03.[2] With an annual parallax shift of 10.54 mas,[1] it is roughly 310 light years from the Sun. At that distance, the visual magnitude of this system is diminished by an extinction factor of 0.22 due to interstellar dust.[6] It is 0.1 degree north of the ecliptic.

This is a single-lined spectroscopic binary star system with an orbital period of 14.48 days and an eccentricity of 0.27.[7] The visible component is a B-type main sequence star with a stellar classification of B3 V.[3] It is a helium-weak chemically peculiar star[12] and a rotating ellipsoidal variable.[4] The star has an estimated 3.9[9] times the radius of the Sun and five times the Sun's mass.[8] This is a candidate Vega-like star, meaning that it shows an infrared excess characteristic of a circumstellar debris disk.[13] The system is a source of X-ray emission.[14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement 15: 459, doi:10.1086/190168, Bibcode: 1968ApJS...15..459G. 
  3. ↑ 3.0 3.1 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode: 1988mcts.book.....H. 
  4. ↑ 4.0 4.1 Hoffleit, Dorrit (1996), "A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars", The Journal of the American Association of Variable Star Observers 24 (2): 105–116, Bibcode: 1996JAVSO..24..105H. 
  5. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics 546: 14, doi:10.1051/0004-6361/201219219, A61, Bibcode: 2012A&A...546A..61D. 
  6. ↑ 6.0 6.1 6.2 Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters 38 (11): 694–706, doi:10.1134/S1063773712110035, Bibcode: 2012AstL...38..694G. 
  7. ↑ 7.0 7.1 Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I. et al. (2004), "SB9: The ninth catalogue of spectroscopic binary orbits", Astronomy & Astrophysics 424 (2): 727–732, doi:10.1051/0004-6361:20041213, Bibcode: 2004A&A...424..727P. 
  8. ↑ 8.0 8.1 8.2 8.3 Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten 331 (4): 349, doi:10.1002/asna.200911355, Bibcode: 2010AN....331..349H. 
  9. ↑ 9.0 9.1 Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics", Astronomy and Astrophysics 367 (2): 521–524, doi:10.1051/0004-6361:20000451, Bibcode: 2001A&A...367..521P. 
  10. ↑ Abt, Helmut A. et al. (2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A. 
  11. ↑ "lam Lib -- Spectroscopic binary", SIMBAD Astronomical Database (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=lam+Lib, retrieved 2017-01-30. 
  12. ↑ Renson, P.; Manfroid, J. (May 2009), "Catalogue of Ap, HgMn and Am stars", Astronomy and Astrophysics 498 (3): 961–966, doi:10.1051/0004-6361/200810788, Bibcode: 2009A&A...498..961R, https://zenodo.org/record/890529. 
  13. ↑ Saffe, C.; Gómez, M.; Pintado, O.; González, E. (October 2008), "Spectroscopic metallicities of Vega-like stars", Astronomy and Astrophysics 490 (1): 297–305, doi:10.1051/0004-6361:200810260, Bibcode: 2008A&A...490..297S. 
  14. ↑ Berghoefer, T. W.; Schmitt, J. H. M. M.; Cassinelli, J. P. (September 1996), "The ROSAT all-sky survey catalogue of optically bright OB-type stars", Astronomy and Astrophysics Supplement 118 (3): 481–494, doi:10.1051/aas:1996213, Bibcode: 1996A&AS..118..481B. 



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