Zeta Canis Majoris

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Zeta Canis Majoris
Diagram showing star positions and boundaries of the Canis Major constellation and its surroundings
Cercle rouge 100%.svg
Location of ζ Canis Majoris (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Canis Major
Right ascension  06h 20m 18.79204s[1]
Declination –30° 03′ 48.1202″[1]
Apparent magnitude (V) +3.025[2]
Spectral type B2.5 V[3]
U−B color index –0.71[2]
B−V color index –0.195[2]
Variable type Suspected β Cep[4]
Radial velocity (Rv)+32.2[5] km/s
Proper motion (μ) RA: +7.32[1] mas/yr
Dec.: +4.03[1] mas/yr
Parallax (π)9.00 ± 0.13[1] mas
Distance362 ± 5 ly
(111 ± 2 pc)
Absolute magnitude (MV)−2.21[6]
Period (P)675 days
Eccentricity (e)0.57
Mass7.7 ± 0.2[8] M
Radius3.9[9] R
Luminosity3,603[10] L
Surface gravity (log g)4.0[9] cgs
Temperature18,700[10] K
Rotational velocity (v sin i)25[11] km/s
Age32.0 ± 0.4[8] Myr
Other designations
Furud, Phurud, ζ CMa, 1 Canis Majoris, CD−30°3038, FK5 240, HD 44402, HIP 30122, HR 2282, SAO 196698.[12]
Database references

Zeta Canis Majoris (ζ Canis Majoris, abbreviated Zeta CMa, ζ CMa), also named Furud /ˈfjʊərəd/,[13] is a spectroscopic binary in the constellation of Canis Major.


Zeta Canis Majoris is the star's Bayer designation assigned by the German astronomer Johann Bayer in 1603.

The traditional name Furud or Phurud derives from the Arabic ألفرود al-furūd "the solitary ones"; this was an apellation early Arab poets used for a number of anonymous stars. Later Arabian astronomers attempted to identify the name with particular stars, principally in the modern constellations Centaurus and Colomba; the stars of Colomba were assigned to Canis Majoris in the Almagest, leading to more recent assignment of the name for Zeta Canis Majoris.[14]

Al Sufi referred to these stars as ألأغربة al-ʼaghribah "the ravens".[15]

In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN)[16] to catalog and standardize proper names for stars; the WGSN's first bulletin of July 2016[17] included a table of the first two batches of names approved by the WGSN; which included Furud for this star.


This star system has an apparent visual magnitude of +3.0,[2] making it one of the brighter stars in the constellation and hence readily visible to the naked eye. Parallax measurements from the Hipparcos mission yield a distance estimate of around 362 ly (111 pc) from the Sun;[1] this is a single-lined spectroscopic binary system, which means that the pair have not been individually resolved with a telescope, but the gravitational perturbations of an unseen astrometric companion can be discerned by shifts in the spectrum of the primary caused by the Doppler effect. The pair orbit around their common center of mass once every 675 days with an eccentricity of 0.57.[7]

The primary component is a large star with nearly four[9] times the Sun's radius and almost eight[8] times the mass of the Sun, it has a stellar classification of B2.5 V,[3] which means it is a B-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. It is emitting 3,603[10] times the luminosity of the Sun and is a suspected Beta Cephei variable;[4] this energy is being radiated from its outer envelope at an effective temperature of about 18,700 K,[10] giving it the blue-white hue of a B-type star.[18] It is relatively young for a star, with an estimated age of 32 million years.[8]

Zeta Canis Majoris is located close to the solar antapex.


  1. ^ a b c d e f van Leeuwen, F. (November 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 Cousins, A. W. J. (1972), "UBV Photometry of Some Very Bright Stars", Monthly Notes of the Astronomical Society of Southern Africa, 31: 69, Bibcode:1972MNSSA..31...69C
  3. ^ a b Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H
  4. ^ a b Telting, J. H.; et al. (June 2006), "A high-resolution spectroscopy survey of β Cephei pulsations in bright stars", Astronomy and Astrophysics, 452 (3): 945–953, Bibcode:2006A&A...452..945T, doi:10.1051/0004-6361:20054730
  5. ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E
  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 Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal, 629 (1): 507–511, Bibcode:2005ApJ...629..507A, doi:10.1086/431207
  8. ^ a b c d 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
  9. ^ a b c Underhill, A. B.; et al. (November 1979), "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars", Monthly Notices of the Royal Astronomical Society, 189 (3): 601–605, Bibcode:1979MNRAS.189..601U, doi:10.1093/mnras/189.3.601
  10. ^ a b c d 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): 349–360, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355
  11. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  12. ^ "zet CMa -- Cepheid variable Star", SIMBAD Astronomical Object Database, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-15
  13. ^ "IAU Catalog of Star Names". Retrieved 28 July 2016.
  14. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  15. ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York: Dover Publications Inc, p. 130, ISBN 0-486-21079-0, retrieved 2010-12-12
  16. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  17. ^ "Bulletin of the IAU Working Group on Star Names, No. 1" (PDF). Retrieved 28 July 2016.
  18. ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, retrieved 2012-01-16

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