Kappa Librae
Kappa Librae, Latinized from κ Librae, is the Bayer designation for a star system in the zodiac constellation of Libra. With an apparent visual magnitude of 4.72,[2] it can be seen with the naked eye. It has an annual parallax shift of 10.57 mas,[1] indicating it lies at a distance of roughly 310 light years.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 15h 41m 56.79858s[1] |
| Declination | −19° 40′ 43.7745″[1] |
| Apparent magnitude (V) | 4.72[2] |
| Characteristics | |
| Spectral type | K5 III[3] |
| U−B color index | +1.94[2] |
| B−V color index | +1.58[2] |
| Astrometry | |
| Radial velocity (Rv) | −4.5±1.5[4] km/s |
| Proper motion (μ) | RA: −32.06[1] mas/yr Dec.: −103.15[1] mas/yr |
| Parallax (π) | 10.57 ± 1.40[1] mas |
| Distance | approx. 310 ly (approx. 90 pc) |
| Absolute magnitude (MV) | −0.62[5] |
| Details | |
| Radius | 38[6] R☉ |
| Luminosity | 296[7] L☉ |
| Temperature | 3,930[7] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
The star shows acceleration components in its proper motion, indicating with high probability that it is an astrometric binary.[9] The visible component is an evolved K-type giant star with a stellar classification of K5 III.[3] It is a suspected variable star with a brightness that ranges between 4.70 and 4.75.[10] The measured angular diameter is 3.71±0.10 mas,[11] which, at the estimated distance of Kappa Librae, yields a physical size of about 38 times the radius of the Sun.[6] It radiates 296 times the solar luminosity from its outer atmosphere at an effective temperature of 3,930 K.[7]
In Chinese astronomy, Kappa Librae is called 日, Pinyin: Rì, meaning Sun, because this star is marking itself and stand alone in Sun asterism, Room mansion (see : Chinese constellation).[12]
References
- van Leeuwen, F. (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.
- Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
- Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
- 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:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61.
- 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.
- Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
- "kap Lib". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-01-30.
- Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal, 129 (5): 2420–2427, Bibcode:2005AJ....129.2420M, doi:10.1086/429590.
- Samus, N. N.; Durlevich, O. V.; et al. (2004), Combined General Catalogue of Variable Stars (GCVS4.2), Bibcode:2004yCat.2250....0S.
- Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431: 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039.
- Ian Ridpath's Startales - Libra the Scales
