 A light curve for KT Lupi, plotted from Hipparcos data | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lupus |
| Right ascension | 15 35 53.24806 |
| Declination | −44° 57′ 30.1982″ |
| Apparent magnitude (V) | 4.55 (4.66 + 6.62) |
| Characteristics | |
| Spectral type | B3 V + B6 V |
| B−V color index | −0.175±0.003 |
| Variable type | Be |
| Astrometry | |
| Radial velocity (Rv) | +6.5±2.8 km/s |
| Proper motion (μ) | RA: −20.53 mas/yr Dec.: −21.23 mas/yr |
| Parallax (π) | 7.62 ± 0.43 mas |
| Distance | 430 ± 20 ly (131 ± 7 pc) |
| Absolute magnitude (MV) | −1.03 |
| Details | |
| KT Lup A | |
| Mass | 5.9±0.1 M☉ |
| Radius | 3.00±0.06 R☉ |
| Luminosity | 794+791 −396 L☉ |
| Surface gravity (log g) | 3.50±0.04 cgs |
| Temperature | 18,400±184 K |
| Rotational velocity (v sin i) | 30±0.6 km/s |
| Age | 21.0±10.6 Myr |
| KT Lup B | |
| Mass | 2.79 M☉ |
| Other designations | |
| d Lup, KT Lup, CD−44°10239, HD 138769, HIP 76371, HR 5781, SAO 225950, WDS J15359-4457AB | |
| Database references | |
| SIMBAD | data |
KT Lupi is a visual binary star system in the constellation Lupus. It is visible to the naked eye with a combined apparent visual magnitude of 4.55. As of 1983, the pair had an angular separation of 2.19″±0.03″. Based upon an annual parallax shift of 7.6 mas as seen from Earth's orbit, it is located 430 light-years from the Sun. The system is moving further from the Earth with a heliocentric radial velocity of +6.5 km/s. It is a member of the Lower Centaurus–Crux sub-group of the Scorpius–Centaurus association.
The primary, component A, is a variable Be star, with the variation being modulated by rotation. It is visual magnitude 4.66 with a stellar classification of B3 V, matching a B-type main-sequence star. Hiltner et al. (1969) gave a class of B3 IVp, which is still used in some studies. It is a helium-weak chemically peculiar star showing an enhanced silicon patch near the equator and a silicon-weak region close to the pole. The star is about 21 million years old with nearly six times the mass of the Sun and three times the Sun's radius. It is radiating roughly 794 times the Sun's luminosity from its photosphere at an effective temperature of 18,400 K.
The secondary companion, component B, is of magnitude 6.62 with a class of B6 V. It has 2.79 times the Sun's mass.
References
- "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
- ^ 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.
- ^ 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.
- ^ Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Chen, Christine H.; et al. (September 2012), "A Spitzer MIPS Study of 2.5-2.0 M⊙ Stars in Scorpius–Centaurus", The Astrophysical Journal, 756 (2): 24, arXiv:1207.3415, Bibcode:2012ApJ...756..133C, doi:10.1088/0004-637X/756/2/133, S2CID 119278056, 133.
- ^ Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
- ^ 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, S2CID 59451347, A61.
- ^ Tetzlaff, N.; et al. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ Arcos, C.; et al. (March 2018), "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey", Monthly Notices of the Royal Astronomical Society, 474 (4): 5287–5299, arXiv:1711.08675, Bibcode:2018MNRAS.474.5287A, doi:10.1093/mnras/stx3075, S2CID 74872624.
- ^ Briquet, M.; et al. (January 2007), "Discovery of magnetic fields in three He variable Bp stars with He and Si spots", Astronomische Nachrichten, 328 (1): 41–45, arXiv:astro-ph/0610537, Bibcode:2007AN....328...41B, doi:10.1002/asna.200610702, S2CID 18724568.
- ^ Kouwenhoven, M. B. N.; et al. (October 2007), "The primordial binary population. II. Recovering the binary population for intermediate mass stars in Scorpius OB2", Astronomy and Astrophysics, 474 (1): 77–104, arXiv:0707.2746, Bibcode:2007A&A...474...77K, doi:10.1051/0004-6361:20077719, S2CID 15750945.
- "KT Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 3 September 2018.
- Briquet, M.; et al. (January 2004), "He and Si surface inhomogeneities of four Bp variable stars", Astronomy and Astrophysics, 413: 273–283, Bibcode:2004A&A...413..273B, doi:10.1051/0004-6361:20031450
- Hiltner, W. A.; et al. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313, Bibcode:1969ApJ...157..313H, doi:10.1086/150069
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