Lambda Columbae

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λ Columbae
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Columba
Right ascension 05h 53m 06.88101s[1]
Declination −33° 48′ 04.9079″[1]
Apparent magnitude (V) 4.86[2]
Spectral type B5 V[3]
U−B color index −0.57[2]
B−V color index −0.15[2]
Variable type Suspected rotating ellipsoidal[4]
Radial velocity (Rv) +30.0[5] km/s
Proper motion (μ) RA: −4.72[1] mas/yr
Dec.: +31.32[1] mas/yr
Parallax (π) 9.75 ± 0.21[1] mas
Distance 335 ± 7 ly
(103 ± 2 pc)
Mass 4.0±0.1[3] M
Radius 3.4[6] R
Luminosity 213[7] L
Surface gravity (log g) 4.22[8] cgs
Temperature 13,524[7] K
Metallicity [Fe/H] −0.06[8] dex
Rotational velocity (v sin i) 88[9] km/s
Age 56.6±26.1[3] Myr
Other designations
λ Col, CD−33° 2599, HD 39764, HIP 27810, HR 2056, SAO 196276.[10]

Lambda Columbae is a probable binary star[11] in the southern constellation of Columba. With an apparent visual magnitude of 4.86,[2] it is faintly visible to the naked eye. The measured annual parallax shift of 9.75 mas[1] yields an estimated distance of roughly 335 light years.

For ancient Arabian astronomers, this star, along with ζ CMa, λ CMa, γ Col, δ Col, θ Col, κ Col, μ Col and ξ Col, formed Al Ḳurūd (ألقرد - al-qird), the Apes.[12] In Chinese, (), meaning Son, refers to an asterism consisting of λ Columbae and β Columbae.[13] Consequently, λ Columbae itself is known as 子一 (Zǐ yī, English: the First Star of Son.).[14] From this Chinese name, the name Tsze is derived.[15]

Lambda Columbae has a stellar classification of B5 V,[3] indicating that it is a B-type main sequence star. It is a suspected rotating ellipsoidal variable[16] with a period of 0.64 days and an amplitude of 0.07 magnitude.[17] Confirmation would indicate that this is a close binary system.[4] It has an estimated age of around 57 million years.[3]


  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:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", SIMBAD, Bibcode:1986EgUBV........0M. 
  3. ^ a b c d e 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:1007.4883Freely accessible, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x. 
  4. ^ a b Samus, N.N.; Durlevich, O.V.; et al. (March 2012), General Catalog of Variable Stars, Institute of Astronomy of Russian Academy of Sciences and Sternberg State Astronomical Institute of the Moscow State University. 
  5. ^ Wilson, R. E. (1953), General Catalogue of Stellar Radial Velocities, Carnegie Institute of Washington, D.C., Bibcode:1953GCRV..C......0W. 
  6. ^ Pasinetti Fracassini, L. E.; et al. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics (3rd ed.), 367: 521–24, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451. 
  7. ^ a b 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:1208.2037Freely accessible, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x. 
  8. ^ a b Hempel, M.; Holweger, H. (September 2003), "Abundance analysis of late B stars. Evidence for diffusion and against weak stellar winds", Astronomy and Astrophysics, 408: 1065−1076, Bibcode:2003A&A...408.1065H, doi:10.1051/0004-6361:20030889. 
  9. ^ Uesugi, Akira; Fukuda, Ichiro (1970), "Catalogue of rotational velocities of the stars", Contributions from the Institute of Astrophysics and Kwasan Observatory, University of Kyoto, 
  10. ^ "lam Col -- Ellipsoidal variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-26. 
  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:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  12. ^ Davis Jr., G. A. (October 1944), "The Pronunciations, Derivations, and Meanings of a Selected List of Star Names", Popular Astronomy, 18: 14, Bibcode:1944PA.....52....8D. 
  13. ^ (Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  14. ^ (Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 16 日
  15. ^ Allen, Richard Hinckley (1963), "Columba Noae, Noah's Dove", Star Names: their Lore and Meaning (Dover ed.). 
  16. ^ Morris, S. L. (August 1985), "The ellipsoidal variable stars", Astrophysical Journal, Part 1, 295: 143−152, Bibcode:1985ApJ...295..143M, doi:10.1086/163359. 
  17. ^ Hoffleit, Dorrit (1996), "A Catalogue of Correlations Between Eclipsing Binaries and Other Categories of Double Stars", The Journal of the American Association of Variable Star Observers, 24 (2): 105−116, Bibcode:1996JAVSO..24..105H.