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2 Lupi
View on Wikipedia| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15h 17m 49.83809s[1] |
| Declination | −30° 08′ 55.2165″[1] |
| Apparent magnitude (V) | 4.33[2] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | K0 IIIa CH-1[3] |
| B−V color index | 1.100±0.004[4] |
| Variable type | none[5] |
| Astrometry | |
| Radial velocity (Rv) | −2.91±0.15[6] km/s |
| Proper motion (μ) | RA: −10.16[1] mas/yr Dec.: −3.66[1] mas/yr |
| Parallax (π) | 10.01±0.21 mas[1] |
| Distance | 326 ± 7 ly (100 ± 2 pc) |
| Absolute magnitude (MV) | −0.65[4] |
| Details | |
| Radius | 11.0+0.7 −0.8[6] R☉ |
| Luminosity | 65.6±0.8[6] L☉ |
| Surface gravity (log g) | 2.84[2] cgs |
| Temperature | 4,953+197 −148[6] K |
| Metallicity [Fe/H] | 0.11[2] dex |
| Other designations | |
| f Lupi, 2 Lup, NSV 7012, CD−29°11630, FK5 3207, HD 135758, HIP 74857, HR 5686, SAO 183346[7] | |
| Database references | |
| SIMBAD | data |
2 Lupi, also known by its Bayer designation f Lupi, is a solitary[8]star in the southern constellation of Lupus,[7] situated approximately 326 light-years away from the Sun.[1] It has the Bayer designation f Lupi; 2 Lupi is the Flamsteed designation. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.33.[2] It is moving closer to the Earth with a heliocentric radial velocity of −3 km/s.[6]
This is an aging giant star with a stellar classification of K0 IIIa CH-1.[3] 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[6] times the Sun's radius. The star is radiating 65.6[6] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,953 K.[6]
2 Lupi is also moving steadily toward our solar system at a rate of roughly –3 km/s. This slow approach is observable through its measured radial velocity[9]
References
[edit]- ^ a b c d e f 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.
- ^ a b c d 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
- ^ a b 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
- ^ a b 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.
- ^ 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.
- ^ a b c d e f g h 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.
- ^ a b "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.
- ^ "2 Lupi - Star in Lupus | TheSkyLive". theskylive.com. Retrieved 2025-08-19.
