Kappa Canis Majoris

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Kappa Canis Majoris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension  06h 49m 50.45933s[1]
Declination −32° 30′ 30.5225″[1]
Apparent magnitude (V) +3.87[2]
Spectral type B1.5 Ve[3] or B1.5 IVe[4]
U−B color index −0.97[2]
B−V color index −0.20[2]
Variable type γ Cas[3]
Radial velocity (Rv)+14.0±4.1[5] km/s
Proper motion (μ) RA: −8.84[1] mas/yr
Dec.: +3.73[1] mas/yr
Parallax (π)4.95 ± 0.12[1] mas
Distance660 ± 20 ly
(202 ± 5 pc)
Absolute magnitude (MV)−3.03[6]
Mass12.2±0.3[7] M
Radius5.9[8] R
Luminosity (bolometric)18,876[9] L
Surface gravity (log g)4.07[8] cgs
Temperature24,600[8] K
Age13.3±1.2[7] Myr
Other designations
κ CMa, 13 Canis Majoris, CD−32°3404, FK5 1180, GC 8946, HD 50013, HIP 32759, HR 2538, SAO 197258[10]
Database references

Kappa Canis Majoris, Latinized from κ Canis Majoris, is a solitary,[11] blue-white hued star in the constellation Canis Major. It is visible to the naked eye with an apparent visual magnitude of +3.87.[2] Based upon an annual parallax shift of 7.70 mas as seen from Earth,[1] this star is located about 660 light years from the Sun.

This is a B-type main-sequence star with a stellar classification of B1.5 Ve,[3] although Hiltner et al. (1969) classified it as B1.5 IVe[4] suggesting it is a subgiant star. The 'e' suffix indicates it is a rapidly rotating Be star with a circumstellar decretion disk of heated gas;[8] the radius of the emitting disk is about 0.20±0.06 AU, or about 3.7 times the radius of the star.[12] It is classified as a Gamma Cassiopeiae type variable star and its brightness varies from magnitude +3.4 to +3.97.[3] The star became 50% brighter between 1963 and 1978, increasing from magnitude 3.96 or so to 3.52.[13]


In Chinese, 弧矢 (Hú Shǐ), meaning Bow and Arrow,[14] refers to an asterism consisting of κ Canis Majoris, δ Canis Majoris, η Canis Majoris, HD 63032, HD 65456, ο Puppis, k Puppis, ε Canis Majoris and π Puppis. Consequently, κ Canis Majoris itself is known as 弧矢八 (Hú Shǐ bā, English: the Eighth Star of Bow and Arrow.)[15]


  1. ^ 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.
  2. ^ a b c d Feinstein, A.; Marraco, H. G. (November 1979), "The photometric behavior of Be Stars", Astronomical Journal, 84: 1713–1725, Bibcode:1979AJ.....84.1713F, doi:10.1086/112600.
  3. ^ a b c d Watson, Christopher (January 4, 2010), "Kappa Canis Majoris", AAVSO Website, American Association of Variable Star Observers, retrieved 2014-02-24.
  4. ^ 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.
  5. ^ 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, A61.
  6. ^ 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.
  7. ^ a b Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (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.
  8. ^ a b c d Meilland, A.; Stee, Ph.; Chesneau, O.; Jones, C. (October 2009), "VLTI/MIDI observations of 7 classical Be stars", Astronomy and Astrophysics, 505 (2): 687–693, arXiv:0908.1239, Bibcode:2009A&A...505..687M, doi:10.1051/0004-6361/200911960.
  9. ^ Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355.
  10. ^ "kap CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-07.
  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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  12. ^ Rivinius, Thomas; et al. (2013), "Classical Be stars. Rapidly rotating B stars with viscous Keplerian decretion disks", The Astronomy and Astrophysics Review, 21: 69, arXiv:1310.3962, Bibcode:2013A&ARv..21...69R, doi:10.1007/s00159-013-0069-0.
  13. ^ Kaler, James B. (March 1, 2013). "Kappa Canis Majoris". Stars. University of Illinois. Retrieved 2014-02-24.
  14. ^ 弧矢 (Hú Shǐ) is westernized into Koo She. R.H. Allen had opinion that Koo She refers to the asterism including δ Velorum and ω Velorum. AEEA opinion is, δ Velorum is member of 天社 (Tiān Shè), meaning Celestial Earth God's Temple asterism and ω Velorum is not member of any asterisms. 天社 (Tiān Shè) is westernized into Tseen She and R.H.Allen used the term Tseen She for Chinese name of η Carinae. See Richard Hinckley Allen: Star Names — Their Lore and Meaning: Argo Navis and ‹See Tfd›(in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日.
  15. ^ ‹See Tfd›(in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 17 日