Delta Librae

δ Librae
Location of δ Librae (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Libra
Right ascension 15h 00m 58.34830s
Declination −08° 31′ 08.2104″
Apparent magnitude (V) 4.93
Characteristics
Evolutionary stage main sequence
Spectral type B9.5V
U−B color index −0.10
B−V color index +0.00
Variable type Algol eclipsing
Astrometry
Radial velocity (Rv)−38.7±2 km/s
Proper motion (μ) RA: −63.051 mas/yr
Dec.: −6.024 mas/yr
Parallax (π)9.2824±0.4725 mas
Distance350 ± 20 ly
(108 ± 5 pc)
Absolute magnitude (MV)+0.15
Orbit
Period (P)2.3273543 days
Semi-major axis (a)12.73±0.34 mas
Eccentricity (e)0.07
Semi-amplitude (K1)
(primary)		76.6 km/s
Semi-amplitude (K2)
(secondary)		218.7 km/s
Details
δ Lib A
Mass3.78±0.13 M☉
Radius3.60±0.13 R☉
Luminosity155+11
−10 L☉
Temperature10,520±110 K
Age0.5 Gyr
δ Lib B
Mass1.50±0.04 M☉
Radius3.79±0.04 R☉
Luminosity9.1+1.4
−1.2 L☉
Temperature5,150±175 K
Other designations
δ Lib, Zuben Elakribi, 19 Librae, BD−07°3938, HD 132742, HIP 73473, HR 5586, SAO 140270
Database references
SIMBADdata

Delta Librae, Latinized from δ Librae, is a variable star in the constellation Libra. It has the traditional name Zuben Elakribi, a variant of the traditional name of Gamma Librae. With μ Virginis it forms one of the Akkadian lunar mansions Mulu-izi (meaning "Man-of-fire").

A light curve for Delta Librae, adapted from Shobbrook (2005)

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

Along with λ Tauri, it was one of the first stars on which rotational line broadening was observed, by Frank Schlesinger in 1911.

References

  1. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 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:2002yCat.2237....0D.
  3. ↑ Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  4. ↑ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  5. 1 2 Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  6. ↑ "Del Lib". The International Variable Star Index. AAVSO – American Association of Variable Star Observers. Retrieved 27 September 2017.
  7. 1 2 Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Carnegie Institute Washington D.C. Publication. Bibcode:1953GCRV..C......0W.
  8. ↑ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  9. 1 2 3 Malkov, Oleg Yu (2020-02-01). "Semidetached double-lined eclipsing binaries: Stellar parameters and rare classes". Monthly Notices of the Royal Astronomical Society. 491 (4): 5489–5497. Bibcode:2020MNRAS.491.5489M. doi:10.1093/mnras/stz3363. ISSN 0035-8711.
  10. 1 2 3 4 5 Tomkin, J. (April 1978). "Secondaries of eclipsing binaries. I. Detection of the secondary of Delta Librae". Astrophysical Journal. 221: 608–615. Bibcode:1978ApJ...221..608T. doi:10.1086/156064.
  11. ↑ 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:astro-ph/0609555. Bibcode:2007ApJ...660.1556R. doi:10.1086/509912. S2CID 11879505.
  12. ↑ Becvar, Antonin (1964). Atlas coeli II - Katalog 1950.0. Bibcode:1964ack..book.....B.
  13. ↑ Allen, R. H. (1963). Star Names: Their Lore and Meaning (rep. ed.). New York, NY: Dover Publications Inc. pp. 277, 473.
  14. ↑ 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.
  15. ↑ Shobbrook, R. R. (December 2005). "Photometry of 20 eclipsing and ellipsoidal binary systems". The Journal of Astronomical Data. 11: 7. Bibcode:2005JAD....11....7S.
  16. ↑ Samus, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General Catalogue of Variable Stars". Astronomy Reports. GCVS 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869. Retrieved 2018-01-07.
  17. ↑ Schlesinger, F. (1909). "Rotation of Stars about their Axes". Monthly Notices of the Royal Astronomical Society. 71 (9): 719. Bibcode:1911MNRAS..71..719S. doi:10.1093/mnras/71.9.719.