Eta Lupi
η Lupi, often Latinised as Eta Lupi, is a probable triple star[4][12] system in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.41.[2] Based upon an annual parallax shift of 27.80[1] mas as seen from Earth, it is located around 136 parsecs (440 ly) distant from the Sun. It is a member of the Upper Centaurus–Lupus subgroup of the nearby Sco OB2 association.[13]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Lupus |
| Right ascension | 16h 00m 07.32786s[1] |
| Declination | −38° 23′ 48.1513″[1] |
| Apparent magnitude (V) | 3.41[2] (3.37 + 7.50 + 10.85)[3] |
| Characteristics | |
| Spectral type | B2 IV + A5 Vp + F5 V[4] |
| U−B color index | −0.83[2] |
| B−V color index | −0.22[2] |
| Astrometry | |
| Radial velocity (Rv) | +1.00±3.80[5] km/s |
| Proper motion (μ) | RA: −16.96[1] mas/yr Dec.: −27.83[1] mas/yr |
| Parallax (π) | 7.38 ± 0.18 mas[1] |
| Distance | 440 ± 10 ly (136 ± 3 pc) |
| Absolute magnitude (MV) | −2.24[6] |
| Details | |
| η Lup A | |
| Mass | 7.0±0.2[7] M☉ |
| Radius | 6.7[8] R☉ |
| Luminosity | 1,729[9] L☉ |
| Temperature | 14,668[9] K |
| Rotational velocity (v sin i) | 242[10] km/s |
| Age | 39.8±9.2[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The inner pair in this triple system has an estimated orbital period of around 27,000 years.[12] As of 2013, they had an angular separation of 15.0 arc seconds along a position angle of 19°.[3] The primary star, component A, is an evolving A-type subgiant star with a stellar classification of B2 IV.[4] It has used up the supply of hydrogen at its core and has begun to expand off the main-sequence.
The secondary, component B, is a chemically peculiar A-type main sequence star with a class of A5 Vp[4] and an estimated mass 2.10 times that of the Sun.[12] The outer member, component C, has an orbital period of around half a million years.[12] As of 2007, it had an angular separation of 115.8 arc seconds along a position angle of 248° from the primary.[3] It is an F-type main sequence star with a classification of F5 V and an estimated 1.29 times the Sun's mass.[12]
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 Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- ^ a b c Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
- ^ a b c d 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.
- ^ 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.
- ^ 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.
- ^ a b 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.
- ^ Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics (3rd ed.), 367: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
- ^ a b 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, S2CID 118665352.
- ^ Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory, University of Kyoto, Bibcode:1970crvs.book.....U
- ^ "eta Lup -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-03-03.
- ^ a b c d e Tokovinin, A. (2008), "Comparative statistics and origin of triple and quadruple stars", Monthly Notices of the Royal Astronomical Society, 389 (2): 925–938, arXiv:0806.3263, Bibcode:2008MNRAS.389..925T, doi:10.1111/j.1365-2966.2008.13613.x, S2CID 16452670.
- ^ 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.
External links edit
- Kaler, James B. (June 24, 2011), "Eta Lupi", Stars, University of Illinois, retrieved 2017-03-04.