# Lambda Librae

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Binary star system in the constellation Libra

Lambda Librae Location of λ Librae (circled in red) Observation data Epoch J2000.0 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 mas[1] Distance 310 ± 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 Mass 5.01±0.26[8] M☉ Radius 3.9[9] R☉ Luminosity 743[8] L☉ Surface gravity (log g) 4.75 cgs Temperature 18,700[8] K Metallicity [Fe/H] −0.27 dex Rotational velocity (v sin i) 155[10] km/s Age 282[6] Myr Other designations λ Lib, 45 Lib, BD−19°4249, FK5 1415, HD 142096, HIP 77811, HR 5902, SAO 183895.[11] Database references SIMBAD data

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

A [light curve](/source/Light_curve) for Lambda Librae, adapted from Wraight *et al.* (2012)[12]

This is a single-lined [spectroscopic binary](/source/Spectroscopic_binary) star system with an [orbital period](/source/Orbital_period) of 14.48 days and an [eccentricity](/source/Orbital_eccentricity) of 0.27.[7] The visible component is a [B-type main sequence star](/source/B-type_main_sequence_star) with a [stellar classification](/source/Stellar_classification) of B3 V.[3] It is a helium-weak [chemically peculiar star](/source/Chemically_peculiar_star)[13] and a [rotating ellipsoidal variable](/source/Rotating_ellipsoidal_variable).[4] The star has an estimated 3.9[9] times the [radius of the Sun](/source/Solar_radius) and five times the [Sun's mass](/source/Solar_mass).[8] This is a candidate [Vega](/source/Vega)-like star, meaning that it shows an [infrared excess](/source/Infrared_excess) characteristic of a circumstellar [debris disk](/source/Debris_disk).[14] The system is a source of [X-ray emission](/source/X-ray_astronomy).[15]

## References

1. ^ [***a***](#cite_ref-vanLeeuwen2007_1-0) [***b***](#cite_ref-vanLeeuwen2007_1-1) [***c***](#cite_ref-vanLeeuwen2007_1-2) [***d***](#cite_ref-vanLeeuwen2007_1-3) [***e***](#cite_ref-vanLeeuwen2007_1-4) [***f***](#cite_ref-vanLeeuwen2007_1-5) van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600).

1. ^ [***a***](#cite_ref-apjs15_2-0) [***b***](#cite_ref-apjs15_2-1) [***c***](#cite_ref-apjs15_2-2) [***d***](#cite_ref-apjs15_2-3) Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", *Astrophysical Journal Supplement*, **15**: 459, [Bibcode](/source/Bibcode_(identifier)):[1968ApJS...15..459G](https://ui.adsabs.harvard.edu/abs/1968ApJS...15..459G), [doi](/source/Doi_(identifier)):[10.1086/190168](https://doi.org/10.1086%2F190168).

1. ^ [***a***](#cite_ref-houk1978_3-0) [***b***](#cite_ref-houk1978_3-1) Houk, Nancy; Smith-Moore, M. (1978), *Michigan catalogue of two-dimensional spectral types for the HD stars*, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, [Bibcode](/source/Bibcode_(identifier)):[1988mcts.book.....H](https://ui.adsabs.harvard.edu/abs/1988mcts.book.....H).

1. ^ [***a***](#cite_ref-Hoffleit1996_4-0) [***b***](#cite_ref-Hoffleit1996_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](/source/Bibcode_(identifier)):[1996JAVSO..24..105H](https://ui.adsabs.harvard.edu/abs/1996JAVSO..24..105H).

1. **[^](#cite_ref-deBruijne2012_5-0)** 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, [arXiv](/source/ArXiv_(identifier)):[1208.3048](https://arxiv.org/abs/1208.3048), [Bibcode](/source/Bibcode_(identifier)):[2012A&A...546A..61D](https://ui.adsabs.harvard.edu/abs/2012A&A...546A..61D), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201219219](https://doi.org/10.1051%2F0004-6361%2F201219219), [S2CID](/source/S2CID_(identifier)) [59451347](https://api.semanticscholar.org/CorpusID:59451347), A61.

1. ^ [***a***](#cite_ref-Gontcharov2012_6-0) [***b***](#cite_ref-Gontcharov2012_6-1) [***c***](#cite_ref-Gontcharov2012_6-2) Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", *Astronomy Letters*, **38** (11): 694–706, [arXiv](/source/ArXiv_(identifier)):[1606.09028](https://arxiv.org/abs/1606.09028), [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..694G](https://ui.adsabs.harvard.edu/abs/2012AstL...38..694G), [doi](/source/Doi_(identifier)):[10.1134/S1063773712110035](https://doi.org/10.1134%2FS1063773712110035), [S2CID](/source/S2CID_(identifier)) [119108982](https://api.semanticscholar.org/CorpusID:119108982).

1. ^ [***a***](#cite_ref-Pourbaix2004_7-0) [***b***](#cite_ref-Pourbaix2004_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, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0406573](https://arxiv.org/abs/astro-ph/0406573), [Bibcode](/source/Bibcode_(identifier)):[2004A&A...424..727P](https://ui.adsabs.harvard.edu/abs/2004A&A...424..727P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20041213](https://doi.org/10.1051%2F0004-6361%3A20041213), [S2CID](/source/S2CID_(identifier)) [119387088](https://api.semanticscholar.org/CorpusID:119387088).

1. ^ [***a***](#cite_ref-Hohle2010_8-0) [***b***](#cite_ref-Hohle2010_8-1) [***c***](#cite_ref-Hohle2010_8-2) [***d***](#cite_ref-Hohle2010_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, [arXiv](/source/ArXiv_(identifier)):[1003.2335](https://arxiv.org/abs/1003.2335), [Bibcode](/source/Bibcode_(identifier)):[2010AN....331..349H](https://ui.adsabs.harvard.edu/abs/2010AN....331..349H), [doi](/source/Doi_(identifier)):[10.1002/asna.200911355](https://doi.org/10.1002%2Fasna.200911355), [S2CID](/source/S2CID_(identifier)) [111387483](https://api.semanticscholar.org/CorpusID:111387483).

1. ^ [***a***](#cite_ref-PasinettiFracassini2001_9-0) [***b***](#cite_ref-PasinettiFracassini2001_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, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0012289](https://arxiv.org/abs/astro-ph/0012289), [Bibcode](/source/Bibcode_(identifier)):[2001A&A...367..521P](https://ui.adsabs.harvard.edu/abs/2001A&A...367..521P), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20000451](https://doi.org/10.1051%2F0004-6361%3A20000451), [S2CID](/source/S2CID_(identifier)) [425754](https://api.semanticscholar.org/CorpusID:425754).

1. **[^](#cite_ref-Abt2002_10-0)** Abt, Helmut A.; et al. (2002), "Rotational Velocities of B Stars", *The Astrophysical Journal*, **573** (1): 359–365, [Bibcode](/source/Bibcode_(identifier)):[2002ApJ...573..359A](https://ui.adsabs.harvard.edu/abs/2002ApJ...573..359A), [doi](/source/Doi_(identifier)):[10.1086/340590](https://doi.org/10.1086%2F340590).

1. **[^](#cite_ref-SIMBAD_11-0)** ["lam Lib -- Spectroscopic binary"](http://simbad.u-strasbg.fr/simbad/sim-id?Ident=lam+Lib), *SIMBAD Astronomical Database*, [Centre de Données astronomiques de Strasbourg](/source/Centre_de_Donn%C3%A9es_astronomiques_de_Strasbourg), retrieved 2017-01-30.

1. **[^](#cite_ref-Wraight_12-0)** Wraight, K. T.; Fossati, L.; Netopil, M.; Paunzen, E.; Rode-Paunzen, M.; Bewsher, D.; Norton, A. J.; White, Glenn J. (February 2012). ["A photometric study of chemically peculiar stars with the STEREO satellites – I. Magnetic chemically peculiar stars"](https://doi.org/10.1111%2Fj.1365-2966.2011.20090.x). *Monthly Notices of the Royal Astronomical Society*. **420** (1): 757–772. [arXiv](/source/ArXiv_(identifier)):[1110.6283](https://arxiv.org/abs/1110.6283). [Bibcode](/source/Bibcode_(identifier)):[2012MNRAS.420..757W](https://ui.adsabs.harvard.edu/abs/2012MNRAS.420..757W). [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2011.20090.x](https://doi.org/10.1111%2Fj.1365-2966.2011.20090.x).

1. **[^](#cite_ref-Renson2009_13-0)** Renson, P.; Manfroid, J. (May 2009), ["Catalogue of Ap, HgMn and Am stars"](https://zenodo.org/record/890529), *Astronomy and Astrophysics*, **498** (3): 961–966, [Bibcode](/source/Bibcode_(identifier)):[2009A&A...498..961R](https://ui.adsabs.harvard.edu/abs/2009A&A...498..961R), [doi](/source/Doi_(identifier)):[10.1051/0004-6361/200810788](https://doi.org/10.1051%2F0004-6361%2F200810788).

1. **[^](#cite_ref-Saffe2008_14-0)** Saffe, C.; Gómez, M.; Pintado, O.; González, E. (October 2008), "Spectroscopic metallicities of Vega-like stars", *Astronomy and Astrophysics*, **490** (1): 297–305, [arXiv](/source/ArXiv_(identifier)):[0805.3936](https://arxiv.org/abs/0805.3936), [Bibcode](/source/Bibcode_(identifier)):[2008A&A...490..297S](https://ui.adsabs.harvard.edu/abs/2008A&A...490..297S), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:200810260](https://doi.org/10.1051%2F0004-6361%3A200810260), [S2CID](/source/S2CID_(identifier)) [15059920](https://api.semanticscholar.org/CorpusID:15059920).

1. **[^](#cite_ref-Berghoefer1996_15-0)** 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, [Bibcode](/source/Bibcode_(identifier)):[1996A&AS..118..481B](https://ui.adsabs.harvard.edu/abs/1996A&AS..118..481B), [doi](/source/Doi_(identifier)):[10.1051/aas:1996213](https://doi.org/10.1051%2Faas%3A1996213).

v t e Constellation of Libra List of stars in Libra Libra in Chinese astronomy Stars Bayer α1 α2 (Zubenelgenubi) β (Zubeneschamali) γ (Zubenelhakrabi) δ ε ζ1 ζ2 ζ3 ζ4 η θ ι1 ι2 κ λ μ ν ξ1 ξ2 ο σ (Brachium) τ υ Flamsteed 2 3 4 5 10 11 12 16 17 18 22 23 26 28 30 36 37 41 42 47 48 49 50 Variable HN HO KU KX HR 5504 5455 HD 133131 134439 134440 135485 137010 139139 140283 141569 141937 Other 2M1510 2MASS 1507−1627 CWISEP J1446−2317 HE 1523−0901 WASP-57 WISE 1534−1043 WISE 1541−2250 Exoplanets 23 Librae b c Gliese 581b c e HD 137010 b (unconfirmed) K2-315b WASP-189b Star clusters NGC 5897 Galaxies NGC 5597 5605 5716 5728 5792 5793 5861 5885 5890 5898 5915 5917 Other AP Librae IC 1059 IRAS 14348−1447 PKS 1510−089 PKS 1519−273 QSO B1524−136 RXC J1504.1−0248 BCG Category

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Adapted from the Wikipedia article [Lambda Librae](https://en.wikipedia.org/wiki/Lambda_Librae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Lambda_Librae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.