Kappa Lupi

Last updated
Kappa Lupi
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Lupus [1] [2]
κ1 Lup
Right ascension 15h 11m 56.07286s [3]
Declination −48° 44′ 16.1692″ [3]
Apparent magnitude  (V)3.86 [4]
κ2 Lup
Right ascension 15h 11m 57.67537s [5]
Declination −48° 44′ 37.2684″ [5]
Apparent magnitude  (V)5.70 [2]
Characteristics
κ1 Lup
Spectral type B9.5 Vne [6]
U−B color index −0.08 [4]
B−V color index −0.05 [4]
κ2 Lup
Evolutionary stage main sequence [5]
Spectral type A3/5V [7]
B−V color index +0.144±0.008 [2]
Astrometry
κ1 Lup
Radial velocity (Rv)−6.6±2.9 [8] km/s
Proper motion (μ)RA: −96.50 [3] mas/yr
Dec.: −49.86 [3] mas/yr
Parallax (π)18.12±0.47  mas [3]
Distance 180 ± 5  ly
(55 ± 1  pc)
κ2 Lup
Radial velocity (Rv)+0.0±3.7 [9] km/s
Proper motion (μ)RA: −98.497 mas/yr [5]
Dec.: −43.645 mas/yr [5]
Parallax (π)17.906 ± 0.0587  mas [5]
Distance 182.1 ± 0.6  ly
(55.8 ± 0.2  pc)
Absolute magnitude  (MV)+1.84 [10]
Details
κ1 Lup
Mass 2.89±0.03 [11]   M☉
Radius 3.0 [12]   R☉
Luminosity 90 [12]   L☉
Surface gravity (log g)3.99±0.14 [13]   cgs
Temperature 10,280 [12]   K
Rotational velocity (v sin i)191±16 [11]  km/s
Age 121 [13]   Myr
κ2 Lup
Mass 2.0 [12]   M☉
Radius 1.8 [12]   R☉
Luminosity13 [12]   L☉
Surface gravity (log g)4.26 [12]   cgs
Temperature 8,255 [12]   K
Metallicity [Fe/H]−0.01 [14]   dex
Rotational velocity (v sin i)160.4±1.0 [15]  km/s
Age 653 [5]   Myr
Other designations
κ1 Lup: CD−48°9704, FK5  1398, HD  134481, HIP  74376, HR  5646, SAO  225525 [16]
κ2 Lup: BD−48°9705, HD 134482, HIP 74380, HR 5647, SAO 225526 [17]
Database references
SIMBAD κ1 Lup
SIMBAD κ2 Lup

Kappa Lupi is a binary star [18] in the constellation of Lupus. With a combined apparent magnitude of 3.70, [19] it is visible to the naked eye. The average distance to this system, based on parallax measurements, is 180 light-years.

The stars in the system are separated by an angular separation of 26.44″ . [18] At their distance, this corresponds to a projected separation of 1,450 astronomical units. [20] They are members of the Hyades Stream, which is a moving group that is coincident with the proper motions of the Hyades cluster. [21]

The primary, Kappa1 Lupi, has an apparent magnitude of 3.86. [4] It is a B-type main sequence star with a stellar classification of B9.5 Vne. [6] 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 million years, [6] it is about 75% of the way through its life span on the main sequence. [11] The star is rotating with a projected rotational velocity of 191 km/s. [11] 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. [22]

The secondary, Kappa2 Lupi, has an apparent magnitude of 5.70. [2] It is an A-type main-sequence star with a stellar classification of A3/5V. [7] The star has a high rotation rate, showing a projected rotational velocity of 160 km/s. [15] It is 2.0 times more massive and 1.8 times larger than the Sun, with 13 times the Sun's luminosity and an effective temperature of 8,255 K. [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). [23]

References

  1. ↑ 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. XHIP record for this object at VizieR.
  2. 1 2 3 4 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. XHIP record for this object at VizieR.
  3. 1 2 3 4 5 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.
  4. 1 2 3 4 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  5. 1 2 3 4 5 6 7 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  6. 1 2 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.
  7. 1 2 Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  8. ↑ 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.
  9. ↑ Kharchenko, N. V.; et al. (2007), "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations", Astronomische Nachrichten, 328 (9): 889, arXiv: 0705.0878 , Bibcode:2007AN....328..889K, doi:10.1002/asna.200710776, S2CID   119323941.
  10. ↑ Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555. arXiv: astro-ph/9911002 . Bibcode:1999A&A...352..555A.
  11. 1 2 3 4 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.
  12. 1 2 3 4 5 6 7 8 9 Stassun, Keivan G.; et al. (2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv: 1905.10694 . Bibcode:2019AJ....158..138S. doi: 10.3847/1538-3881/ab3467 .
  13. 1 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, arXiv: 1501.03154 , Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID   33401607.
  14. ↑ Netopil, Martin (August 2017), "Metallicity calibrations for dwarf stars and giants in the Geneva photometric system", Monthly Notices of the Royal Astronomical Society, 469 (3): 3042–3055, arXiv: 1705.00883 , Bibcode:2017MNRAS.469.3042N, doi: 10.1093/mnras/stx1077 , S2CID   119034918.
  15. 1 2 Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv: 1012.4858 , Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386, S2CID   119286673.
  16. ↑ "kap01 Lup". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2017-03-07.{{cite web}}: CS1 maint: postscript (link)
  17. ↑ "kap02 lup". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2019-09-14.
  18. 1 2 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.
  19. ↑ Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D.
  20. ↑ 26.44" •55 pc = 1,450 AU.
  21. ↑ Eggen, Olin J. (1996), "The Stellar Content of Star Stream I", Astronomical Journal, 111: 1615, Bibcode:1996AJ....111.1615E, doi:10.1086/117901
  22. ↑ 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.
  23. ↑ (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
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