| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15 17 49.83809 |
| Declination | −30° 08′ 55.2165″ |
| Apparent magnitude (V) | 4.33 |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K0 IIIa CH-1 |
| B−V color index | 1.100±0.004 |
| Astrometry | |
| Radial velocity (Rv) | −2.91±0.15 km/s |
| Proper motion (μ) | RA: −10.16 mas/yr Dec.: −3.66 mas/yr |
| Parallax (π) | 10.01 ± 0.21 mas |
| Distance | 326 ± 7 ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.65 |
| Details | |
| Radius | 11.0+0.7 −0.8 R☉ |
| Luminosity | 65.6±0.8 L☉ |
| Surface gravity (log g) | 2.84 cgs |
| Temperature | 4,953+197 −148 K |
| Metallicity | 0.11 dex |
| Other designations | |
| f Lupi, 2 Lup, NSV 7012, CD−29°11630, FK5 3207, HD 135758, HIP 74857, HR 5686, SAO 183346 | |
| Database references | |
| SIMBAD | data |
2 Lupi is a single star in the southern constellation of Lupus, located 326 light-years away from the Sun. It has the Bayer designation f Lupi; 2 Lupi is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.33. It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.
This is an aging giant star with a stellar classification of K0 IIIa CH-1. The suffix notation indicates abnormally weak lines of carbyne. Having exhausted the hydrogen at its core, the star evolved away from the main sequence by expanding to 11 times the Sun's radius. The star is radiating 65.6 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,953 K. It is a suspected variable star of unknown type.
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, S2CID 18759600.
- ^ McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527
- ^ Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373
- ^ 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.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ "2 Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-04-06.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
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