Kappa1 Lupi

Kappa¹ Lupi is a solitary^[9] 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.^[10] 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.^[11]

For other stars with this Bayer designation, see κ Lupi.

Kappa¹ Lupi

Observation data Epoch J2000.0      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]
Characteristics
Spectral type	B9.5 Vne[3]
U−B color index	−0.08[2]
B−V color index	−0.05[2]
Astrometry
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 mas[1]
Distance	180 ± 5 ly (55 ± 1 pc)
Details
Mass	2.89±0.03[5] M☉
Radius	2.3[6] R☉
Luminosity	151[3] L☉
Surface gravity (log g)	3.99±0.14[7] cgs
Temperature	11,305±384[7] K
Rotational velocity (v sin i)	191±16[5] km/s
Age	121[7] Myr
Other designations
κ1 Lup, CD−48° 9704, FK5 1398, HD 134481, HIP 74376, HR 5646, SAO 225525.[8]
Database references
SIMBAD	data

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.^[5] The star is rotating with a projected rotational velocity of 191 km/s.^[5] 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.^[12]

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).^[13]

References

1. 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. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
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, arXiv:astro-ph/0606149, Bibcode:2006MNRAS.371..252L, doi:10.1111/j.1365-2966.2006.10655.x, S2CID 16492030.
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. Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
6. 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.
7. 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, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
8. "kap Lup". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-03-07.{{cite web}}: CS1 maint: postscript (link)
9. 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, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x, S2CID 119120749.
10. 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.
11. Eggen, Olin J. (1996), "The Stellar Content of Star Stream I", Astronomical Journal, 111: 1615, Bibcode:1996AJ....111.1615E, doi:10.1086/117901
12. 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.
13. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 6 月 29 日 Archived 2021-06-05 at the Wayback Machine

External links

• Kaler, James B. (August 17, 2012), "Kappa Lupi", Stars, University of Illinois, archived from the original on January 17, 2019, retrieved March 8, 2017.