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Theta Lupi

Theta Lupi, Latinized from θ Lupi, is a solitary[12] star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 4.22.[2] (The planetary nebula NGC 6072 lies 1.4° to the east-northeast.[13]) Based upon an annual parallax shift of 7.87 mas as seen from Earth, it is located roughly 410 light years away from the Sun. Relative to its neighbors, this star has a peculiar velocity of 16.7±3.7 km/s.[14] It is a member of the nearby Sco OB2 association.[12]

Theta Lupi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Lupus
Right ascension 16h 06m 35.54525s[1]
Declination −36° 48′ 08.2653″[1]
Apparent magnitude (V) 4.22[2]
Characteristics
Spectral type B2.5 Vn[3]
U−B color index −0.734[2]
B−V color index −0.184[2]
Astrometry
Radial velocity (Rv)+6.0±3.4[4] km/s
Proper motion (μ) RA: −15.33[1] mas/yr
Dec.: −33.83[1] mas/yr
Parallax (π)7.87 ± 0.47 mas[1]
Distance410 ± 20 ly
(127 ± 8 pc)
Absolute magnitude (MV)−1.29[5]
Details
Mass6.5±0.1[6] M☉
Radius4.5[7] R☉
Luminosity792[8] L☉
Surface gravity (log g)4.5[9] cgs
Temperature15,395[8] K
Rotational velocity (v sin i)331[10] km/s
Age24.6±5.2[6] Myr
Other designations
θ Lup, CD−36° 10642, FK5 599, HD 144294, HIP 78918, HR 5987, SAO 207332.[11]
Database references
SIMBADdata

This is a B-type main sequence star with a stellar classification of B2.5 Vn,[3] where the 'n' suffix indicates nebulous lines due to spin. It is rotating rapidly with a projected rotational velocity of 331 km/s.[10] This is giving the star an oblate shape with an equatorial bulge that is an estimated 15% larger than the polar radius.[15] The star has an estimated 6.5[6] times the mass of the Sun and around 4.5[7] times the Sun's radius. With an age of just 24.6[6] million years, it is radiating 792 times the solar luminosity from its outer atmosphere at an effective temperature of 15,395 K.[8]

References

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  1. ^ a b c d e 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.
  2. ^ a b c d Gutierrez-Moreno, Adelina; Moreno, Hugo (1968), "A Photometric Investigation of the Scorpio-Centaurus Association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
  3. ^ a b Hiltner, W. A.; et al. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313–326, Bibcode:1969ApJ...157..313H, doi:10.1086/150069.
  4. ^ 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.
  5. ^ 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.
  6. ^ a b c d 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.
  7. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics, 367 (3rd ed.): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  8. ^ a b c 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.
  9. ^ Gullikson, Kevin; et al. (August 2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 13, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065, 40.
  10. ^ a b 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.
  11. ^ "tet Lup -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-03-03.
  12. ^ a b Rizzuto, A. C.; et al. (December 2013), "Long-baseline interferometric multiplicity survey of the Sco-Cen OB association", Monthly Notices of the Royal Astronomical Society, 436 (2): 1694–1707, arXiv:1309.3811, Bibcode:2013MNRAS.436.1694R, doi:10.1093/mnras/stt1690.
  13. ^ Bakich, Michael E. (2010), 1,001 Celestial Wonders to See Before You Die: The Best Sky Objects for Star Gazers, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 191, ISBN 978-1441917775.
  14. ^ Bobylev, V. V.; Bajkova, A. T. (August 2013), "Galactic kinematics from a sample of young massive stars", Astronomy Letters, 39 (8): 532–549, arXiv:1307.1677, Bibcode:2013AstL...39..532B, doi:10.1134/S106377371308001X, S2CID 118568203.
  15. ^ Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
edit
  • Kaler, James B. (July 12, 2013), "Theta Lupi", Stars, University of Illinois, retrieved 2017-03-05.
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