Astronomy:Kappa1 Lupi

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Short description: Star in the constellation Lupus

Kappa1 Lupi
Observation data
Equinox J2000.0]] (ICRS)
Constellation Lupus
Right ascension  15h 11m 56.07286s[1]
Declination −48° 44′ 16.1692″[1]
Apparent magnitude (V) 3.86[2]
Spectral type B9.5 Vne[3]
U−B color index −0.08[2]
B−V color index −0.05[2]
Radial velocity (Rv)−6.6±2.9[4] km/s
Proper motion (μ) RA: −96.50[1] mas/yr
Dec.: −49.86[1] mas/yr
Parallax (π)18.12 ± 0.47[1] mas
Distance180 ± 5 ly
(55 ± 1 pc)
Absolute magnitude (MV)+3.82[5]
Mass2.89±0.03[6] M
Radius2.3[7] R
Luminosity151[3] L
Surface gravity (log g)3.99±0.14[8] cgs
Temperature11,305±384[8] K
Rotational velocity (v sin i)191±16[6] km/s
Age121[8] Myr
Other designations
κ1 Lup, CD−48° 9704, FK5 1398, HD 134481, HIP 74376, HR 5646, SAO 225525.[9]
Database references

Kappa1 Lupi is a solitary[10] star in the southern constellation of Lupus. It is visible to the naked eye with an apparent visual magnitude of 3.86,[2] and forms a double star with Kappa2 Lupi.[11] Based upon an annual parallax shift of 18.12[1] mas as seen from Earth, it is located about 180 light years from the Sun. Both Kappa1 Lupi and its neighbor Kappa2 Lupi are members of the Hyades Stream, which is a moving group that is coincident with the proper motions of the Hyades cluster.[12]

This is a B-type main sequence star with a stellar classification of B9.5 Vne.[3] The 'n' suffix indicates the spectrum shows "nebulous" absorption lines due to rapid rotation, while the 'e' means this is a Be star that displays Balmer series emission lines. With an estimated age of 195[3] million years, it is about 75% of the way through its life span on the main sequence.[6] The star is rotating with a projected rotational velocity of 191 km/s.[6] This rate of spin is giving the star an oblate shape with an equatorial bulge that is an estimated 9% larger than the polar radius.[13]

In Chinese astronomy, Kappa1 Lupi is called 騎陣將軍, Pinyin: Qízhènjiāngjūn, meaning Chariots and Cavalry General, because this star is marking itself and stand alone in Chariots and Cavalry General asterism, Root mansion (see : Chinese constellation).[14]


  1. 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode2007A&A...474..653V. 
  2. 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode1986EgUBV........0M. 
  3. 3.0 3.1 3.2 3.3 Levenhagen, R. S.; Leister, N. V. (2006), "Spectroscopic analysis of southern B and Be stars", Monthly Notices of the Royal Astronomical Society 371 (1): 252–262, doi:10.1111/j.1365-2966.2006.10655.x, Bibcode2006MNRAS.371..252L. 
  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, doi:10.1051/0004-6361/201219219, A61, Bibcode2012A&A...546A..61D. 
  5. Levenhagen, R. S.; Leister, N. V. (February 2004), "Physical Parameters of Southern B- and Be-Type Stars", The Astronomical Journal 127 (2): 1176–1180, doi:10.1086/381063, Bibcode2004AJ....127.1176L. 
  6. 6.0 6.1 6.2 6.3 Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics 537: A120, doi:10.1051/0004-6361/201117691, Bibcode2012A&A...537A.120Z. 
  7. Pasinetti Fracassini, L. E. et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy and Astrophysics 367: 521–524, doi:10.1051/0004-6361:20000451, Bibcode2001A&A...367..521P. 
  8. 8.0 8.1 8.2 David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal 804 (2): 146, doi:10.1088/0004-637X/804/2/146, Bibcode2015ApJ...804..146D. 
  9. "kap Lup". SIMBAD. Centre de données astronomiques de Strasbourg. 
  10. Chini, R. et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society 424 (3): 1925, doi:10.1111/j.1365-2966.2012.21317.x, Bibcode2012MNRAS.424.1925C. 
  11. 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E. 
  12. Eggen, Olin J. (1996), "The Stellar Content of Star Stream I", Astronomical Journal 111: 1615, doi:10.1086/117901, Bibcode1996AJ....111.1615E 
  13. Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode2012A&ARv..20...51V. 
  14. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日

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