Astronomy:Delta Librae

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Short description: Binary star in the constellation Libra
δ Librae
Location of δ Librae (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
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[1] mas
Distance350 ± 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
Mass3.78±0.13 M☉
Radius3.60±0.13 R☉
Luminosity155+11
−10 L☉
Temperature10,520±110 K
Age0.5[11] 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.[12] With μ Virginis it forms one of the Akkadian lunar mansions Mulu-izi[13] (meaning "Man-of-fire").[14]

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

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[2] and is moving closer to the Sun with a radial velocity of −39 km/s.[7] This is an Algol-like eclipsing binary star system, with a period of 2.3274 days and an eccentricity of 0.07.[10] Its apparent magnitude varies from 4.91 to 5.90.[16] 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.[10]

Along with λ Tauri, it was one of the first stars on which rotational line broadening was observed, by Frank Schlesinger in 1911.[17]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. ↑ 2.0 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: 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. doi:10.1051/0004-6361/201117691. Bibcode: 2012A&A...537A.120Z. 
  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. ↑ 5.0 5.1 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. http://www.aavso.org/vsx/index.php?view=detail.top&oid=17591. 
  7. ↑ 7.0 7.1 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. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  9. ↑ 9.0 9.1 9.2 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. doi:10.1093/mnras/stz3363. ISSN 0035-8711. Bibcode: 2020MNRAS.491.5489M. 
  10. ↑ 10.0 10.1 10.2 10.3 10.4 Tomkin, J. (April 1978). "Secondaries of eclipsing binaries. I. Detection of the secondary of Delta Librae". Astrophysical Journal 221: 608–615. doi:10.1086/156064. Bibcode: 1978ApJ...221..608T. 
  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. doi:10.1086/509912. Bibcode: 2007ApJ...660.1556R. 
  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. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S. http://www.sai.msu.su/gcvs/cgi-bin/search.cgi?search=del+lib. Retrieved 2018-01-07. 
  17. ↑ Schlesinger, F. (1909). "Rotation of Stars about their Axes". Monthly Notices of the Royal Astronomical Society 71 (9): 719. doi:10.1093/mnras/71.9.719. Bibcode: 1911MNRAS..71..719S. 



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