# Delta Librae

> Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Delta_Librae
> Markdown URL: https://mediated.wiki/source/Delta_Librae.md
> Source: https://en.wikipedia.org/wiki/Delta_Librae
> Source revision: 1344980552
> License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/)

Binary star in the constellation Libra

δ Librae Location of δ Librae (circled in red) Observation data Epoch J2000 Equinox J2000 Constellation Libra Right ascension 15h 00m 58.34830s[1] Declination −08° 31′ 08.2104″[1] Apparent magnitude (V) 4.93[2] Characteristics Evolutionary stage main sequence[3] Spectral type B9.5V[4] U−B color index −0.10[5] B−V color index +0.00[5] Variable type Algol eclipsing[6] Astrometry Radial velocity (Rv) −38.7±2[7] km/s Proper motion (μ) RA: −63.051[1] mas/yr Dec.: −6.024[1] mas/yr Parallax (π) 9.2824±0.4725 mas[1] Distance 350 ± 20 ly (108 ± 5 pc) Absolute magnitude (MV) +0.15[8] Orbit Period (P) 2.3273543 days[9] Semi-major axis (a) 12.73±0.34 mas[9] Eccentricity (e) 0.07[10] Semi-amplitude (K1) (primary) 76.6[10] km/s Semi-amplitude (K2) (secondary) 218.7[10] km/s Details[9] δ Lib A Mass 3.78±0.13 M☉ Radius 3.60±0.13 R☉ Luminosity 155+11 −10 L☉ Temperature 10,520±110 K Age 0.5[11] Gyr δ Lib B Mass 1.50±0.04 M☉ Radius 3.79±0.04 R☉ Luminosity 9.1+1.4 −1.2 L☉ Temperature 5,150±175 K Other designations δ Lib, Zuben Elakribi, 19 Librae, BD−07°3938, HD 132742, HIP 73473, HR 5586, SAO 140270 Database references SIMBAD data

**Delta Librae**, [Latinized](/source/Romanization_of_Greek) from δ Librae, is a [variable star](/source/Variable_star) in the [constellation](/source/Constellation) [Libra](/source/Libra_(constellation)). It has the traditional name *Zuben Elakribi*, a variant of the traditional name of [Gamma Librae](/source/Gamma_Librae).[12] With [μ Virginis](/source/%CE%9C_Virginis) it forms one of the [Akkadian](/source/Akkadian_language) [lunar mansions](/source/Lunar_mansion) *Mulu-izi*[13] (meaning "Man-of-fire").[14]

A [light curve](/source/Light_curve) for Delta Librae, adapted from Shobbrook (2005)[15]

δ Librae is approximately 350 [light years](/source/Light_year) from the [Earth](/source/Earth) and the primary, component A, belongs to the [spectral class](/source/Stellar_classification) B9.5V, indicating it is a [B-type main-sequence star](/source/B-type_main-sequence_star). It is visible to the naked eye with an [apparent visual magnitude](/source/Apparent_visual_magnitude) of 4.93[2] and is moving closer to the Sun with a [radial velocity](/source/Radial_velocity) of −39 km/s.[7] This is an [Algol](/source/Algol)-like [eclipsing binary](/source/Eclipsing_binary) star system, with a [period](/source/Orbital_period) of 2.3274 days and an [eccentricity](/source/Orbital_eccentricity) of 0.07.[10] Its [apparent magnitude](/source/Apparent_magnitude) varies from 4.91 to 5.90.[16] The secondary is filling its [Roche lobe](/source/Roche_lobe) and there is evidence of large-scale mass transfer in the past, with the secondary being more [evolved](/source/Stellar_evolution) than the primary despite now being less massive.[10]

Along with [λ Tauri](/source/%CE%9B_Tauri), it was one of the first stars on which rotational line broadening was observed, by [Frank Schlesinger](/source/Frank_Schlesinger) in 1911.[17]

## References

1. ^ [***a***](#cite_ref-dr3_1-0) [***b***](#cite_ref-dr3_1-1) [***c***](#cite_ref-dr3_1-2) [***d***](#cite_ref-dr3_1-3) [***e***](#cite_ref-dr3_1-4) Vallenari, A.; et al. (Gaia collaboration) (2023). ["*Gaia* Data Release 3. Summary of the content and survey properties"](https://doi.org/10.1051%2F0004-6361%2F202243940). *Astronomy and Astrophysics*. **674**: A1. [arXiv](/source/ArXiv_(identifier)):[2208.00211](https://arxiv.org/abs/2208.00211). [Bibcode](/source/Bibcode_(identifier)):[2023A&A...674A...1G](https://ui.adsabs.harvard.edu/abs/2023A&A...674A...1G). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202243940](https://doi.org/10.1051%2F0004-6361%2F202243940). [S2CID](/source/S2CID_(identifier)) [244398875](https://api.semanticscholar.org/CorpusID:244398875). [Gaia DR3 record for this source](https://vizier.cds.unistra.fr/viz-bin/VizieR-4?-source=+I%2F355&-from=nav&-nav=cat%3AI%2F355%26tab%3A%7BI%2F355%2Fgaiadr3%7D%26key%3Asource%3D1355%2Fgaiadr3%26HTTPPRM%3A%26-out.add%3D.%26Source%3D%3D%3D6332277920392457472%26-go+%25%23Sesame%23%25%26) at [VizieR](/source/VizieR).

1. ^ [***a***](#cite_ref-Ducati2002_2-0) [***b***](#cite_ref-Ducati2002_2-1) Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". *CDS/ADC Collection of Electronic Catalogues*. **2237**. [Bibcode](/source/Bibcode_(identifier)):[2002yCat.2237....0D](https://ui.adsabs.harvard.edu/abs/2002yCat.2237....0D).

1. **[^](#cite_ref-zorec2012_3-0)** Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". *Astronomy and Astrophysics*. **537**: A120. [arXiv](/source/ArXiv_(identifier)):[1201.2052](https://arxiv.org/abs/1201.2052). [Bibcode](/source/Bibcode_(identifier)):[2012A&A...537A.120Z](https://ui.adsabs.harvard.edu/abs/2012A&A...537A.120Z). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/201117691](https://doi.org/10.1051%2F0004-6361%2F201117691).

1. **[^](#cite_ref-HD_4-0)** Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". *Michigan Spectral Survey*. **5**. [Bibcode](/source/Bibcode_(identifier)):[1999MSS...C05....0H](https://ui.adsabs.harvard.edu/abs/1999MSS...C05....0H).

1. ^ [***a***](#cite_ref-UBV_5-0) [***b***](#cite_ref-UBV_5-1) Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". *Communications of the Lunar and Planetary Laboratory*. **4**: 99. [Bibcode](/source/Bibcode_(identifier)):[1966CoLPL...4...99J](https://ui.adsabs.harvard.edu/abs/1966CoLPL...4...99J).

1. **[^](#cite_ref-magnitude_6-0)** ["Del Lib"](http://www.aavso.org/vsx/index.php?view=detail.top&oid=17591). *The International Variable Star Index*. AAVSO – American Association of Variable Star Observers. Retrieved 27 September 2017.

1. ^ [***a***](#cite_ref-GCRV_7-0) [***b***](#cite_ref-GCRV_7-1) Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". *Carnegie Institute Washington D.C. Publication*. [Bibcode](/source/Bibcode_(identifier)):[1953GCRV..C......0W](https://ui.adsabs.harvard.edu/abs/1953GCRV..C......0W).

1. **[^](#cite_ref-Anderson2012_8-0)** Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". *Astronomy Letters*. **38** (5): 331. [arXiv](/source/ArXiv_(identifier)):[1108.4971](https://arxiv.org/abs/1108.4971). [Bibcode](/source/Bibcode_(identifier)):[2012AstL...38..331A](https://ui.adsabs.harvard.edu/abs/2012AstL...38..331A). [doi](/source/Doi_(identifier)):[10.1134/S1063773712050015](https://doi.org/10.1134%2FS1063773712050015). [S2CID](/source/S2CID_(identifier)) [119257644](https://api.semanticscholar.org/CorpusID:119257644).

1. ^ [***a***](#cite_ref-Malkov2020_9-0) [***b***](#cite_ref-Malkov2020_9-1) [***c***](#cite_ref-Malkov2020_9-2) Malkov, Oleg Yu (2020-02-01). ["Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes"](https://doi.org/10.1093%2Fmnras%2Fstz3363). *Monthly Notices of the Royal Astronomical Society*. **491** (4): 5489–5497. [Bibcode](/source/Bibcode_(identifier)):[2020MNRAS.491.5489M](https://ui.adsabs.harvard.edu/abs/2020MNRAS.491.5489M). [doi](/source/Doi_(identifier)):[10.1093/mnras/stz3363](https://doi.org/10.1093%2Fmnras%2Fstz3363). [ISSN](/source/ISSN_(identifier)) [0035-8711](https://search.worldcat.org/issn/0035-8711).

1. ^ [***a***](#cite_ref-Tomkin1978_10-0) [***b***](#cite_ref-Tomkin1978_10-1) [***c***](#cite_ref-Tomkin1978_10-2) [***d***](#cite_ref-Tomkin1978_10-3) [***e***](#cite_ref-Tomkin1978_10-4) Tomkin, J. (April 1978). ["Secondaries of eclipsing binaries. I. Detection of the secondary of Delta Librae"](https://doi.org/10.1086%2F156064). *Astrophysical Journal*. **221**: 608–615. [Bibcode](/source/Bibcode_(identifier)):[1978ApJ...221..608T](https://ui.adsabs.harvard.edu/abs/1978ApJ...221..608T). [doi](/source/Doi_(identifier)):[10.1086/156064](https://doi.org/10.1086%2F156064).

1. **[^](#cite_ref-Rhee_11-0)** Rhee, Joseph H.; Song, Inseok; Zuckerman, B.; McElwain, Michael (2007). "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs". *The Astrophysical Journal*. **660** (2): 1556–1571. [arXiv](/source/ArXiv_(identifier)):[astro-ph/0609555](https://arxiv.org/abs/astro-ph/0609555). [Bibcode](/source/Bibcode_(identifier)):[2007ApJ...660.1556R](https://ui.adsabs.harvard.edu/abs/2007ApJ...660.1556R). [doi](/source/Doi_(identifier)):[10.1086/509912](https://doi.org/10.1086%2F509912). [S2CID](/source/S2CID_(identifier)) [11879505](https://api.semanticscholar.org/CorpusID:11879505).

1. **[^](#cite_ref-ACII_12-0)** Becvar, Antonin (1964). *Atlas coeli II - Katalog 1950.0*. [Bibcode](/source/Bibcode_(identifier)):[1964ack..book.....B](https://ui.adsabs.harvard.edu/abs/1964ack..book.....B).

1. **[^](#cite_ref-Allen_13-0)** [Allen, R. H.](/source/Richard_Hinckley_Allen) (1963). *[Star Names: Their Lore and Meaning](/source/Star_Names%3A_Their_Lore_and_Meaning)* ([rep](/source/Reprint). ed.). [New York](/source/New_York_City), [NY](/source/New_York_(state)): [Dover Publications](/source/Dover_Publications) Inc. pp. 277, 473.

1. **[^](#cite_ref-Brown_14-0)** Brown Jr., R. (1891). "Remarks on the Euphratean Astronomical Names of the Signs of the Zodiac". *Proceedings of the Society of Biblical Archaeology*. **13**: 194.

1. **[^](#cite_ref-Shobbrook_15-0)** Shobbrook, R. R. (December 2005). "Photometry of 20 eclipsing and ellipsoidal binary systems". *The Journal of Astronomical Data*. **11**: 7. [Bibcode](/source/Bibcode_(identifier)):[2005JAD....11....7S](https://ui.adsabs.harvard.edu/abs/2005JAD....11....7S).

1. **[^](#cite_ref-gcvs_16-0)** Samus, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). ["General Catalogue of Variable Stars"](http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=del+lib). *Astronomy Reports*. GCVS 5.1. **61** (1): 80–88. [Bibcode](/source/Bibcode_(identifier)):[2017ARep...61...80S](https://ui.adsabs.harvard.edu/abs/2017ARep...61...80S). [doi](/source/Doi_(identifier)):[10.1134/S1063772917010085](https://doi.org/10.1134%2FS1063772917010085). [S2CID](/source/S2CID_(identifier)) [125853869](https://api.semanticscholar.org/CorpusID:125853869). Retrieved 2018-01-07.

1. **[^](#cite_ref-test_17-0)** Schlesinger, F. (1909). ["Rotation of Stars about their Axes"](https://doi.org/10.1093%2Fmnras%2F71.9.719). *[Monthly Notices of the Royal Astronomical Society](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*. **71** (9): 719. [Bibcode](/source/Bibcode_(identifier)):[1911MNRAS..71..719S](https://ui.adsabs.harvard.edu/abs/1911MNRAS..71..719S). [doi](/source/Doi_(identifier)):[10.1093/mnras/71.9.719](https://doi.org/10.1093%2Fmnras%2F71.9.719).

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

---
Adapted from the Wikipedia article [Delta Librae](https://en.wikipedia.org/wiki/Delta_Librae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Delta_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.