Delta Librae
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.[10] With μ Vir it forms one of the Akkadian lunar mansions Mulu-izi[11] (meaning "Man-of-fire"[12]).
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 00m 58.35013s[1] |
| Declination | −08° 31′ 08.2063″[1] |
| Apparent magnitude (V) | 4.93[2] |
| Characteristics | |
| Spectral type | B9.5V[3] |
| U−B color index | –0.10[4] |
| B−V color index | +0.00[4] |
| Variable type | Eclipsing binary of Algol type (EA/SD)[5] |
| Astrometry | |
| Radial velocity (Rv) | −38.7±2[6] km/s |
| Proper motion (μ) | RA: -63.46[1] mas/yr Dec.: -4.76[1] mas/yr |
| Parallax (π) | 11.11 ± 0.60[1] mas |
| Distance | 290 ± 20 ly (90 ± 5 pc) |
| Absolute magnitude (MV) | +0.15[7] |
| Orbit[8] | |
| Period (P) | 2.3274 d |
| Eccentricity (e) | 0.07 |
| Semi-amplitude (K1) (primary) | 76.6 km/s |
| Semi-amplitude (K2) (secondary) | 218.7 km/s |
| Details | |
| δ Lib A | |
| Mass | 4.9±0.2[8] M☉ |
| Radius | 3.94[9] R☉ |
| Luminosity | 86[7] L☉ |
| Temperature | 8800[9] K |
| Age | 0.5[9] Gyr |
| δ Lib B | |
| Mass | 1.7±0.2[8] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
δ Lib is approximately 300 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.[6] This is an Algol-like eclipsing binary star system, with a period of 2.3274 days and an eccentricity of 0.07.[8] Its apparent magnitude varies from 4.91m to 5.9m.[13] The secondary is filling its roche lobe and there is evidence of large-scale mass transfer in the past, with the star being more evolved than the primary.[8]
Along with λ Tau, it was one of the first stars on which rotational line broadening[14] was observed, by Frank Schlesinger in 1911.
References
- van Leeuwen, F.; et al. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- 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.
- 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.
- Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4. Bibcode:1966CoLPL...4...99J.
- "Del Lib". The International Variable Star Index. AAVSO – American Association of Variable Star Observers. Retrieved 27 September 2017.
- Wilson, Ralph Elmer (1953). "General catalogue of stellar radial velocities". Bibcode:1953GCRV..C......0W. Cite journal requires
|journal=(help) - 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.
- 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.
- 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.
- Bečvář, A., Atlas Coeli II Atlas Coeli II- Catalog, Ceskoslovenské Akademie Ved, Praha,1959.
- Allen, R. H. (1963). Star Names: Their Lore and Meaning (rep. ed.). New York, NY: Dover Publications Inc. pp. 277, 473.
- Brown Jr., R., (1891). "Remarks on the Euphratean Astronomical Names of the Signs of the Zodiac", Proceedings of the Society of Biblical Archaeology, vo. 13, p. 194.
- 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, retrieved 2018-01-07.
- Schlesinger, F. (1909), "Rotation of Stars about their Axes", Monthly Notices of the Royal Astronomical Society, 71: 719, Bibcode:1911MNRAS..71..719S, doi:10.1093/mnras/71.9.719.