Zeta Canis Majoris

Zeta Canis Majoris
Location of ζ Canis Majoris (circled)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Canis Major
Right ascension 06h 20m 18.79204s
Declination −30° 03′ 48.1202″
Apparent magnitude (V) +3.025
Characteristics
Spectral type B2.5 V
U−B color index −0.71
B−V color index −0.195
Variable type SPB
Astrometry
Radial velocity (Rv)+32.2 km/s
Proper motion (μ) RA: +7.32 mas/yr
Dec.: +4.03 mas/yr
Parallax (π)9.00±0.13 mas
Distance362 ± 5 ly
(111 ± 2 pc)
Absolute magnitude (MV)−2.21
Orbit
Period (P)675 days
Eccentricity (e)0.57
Periastron epoch (T)2,416,508 JD
Argument of periastron (ω)
(secondary)		207°
Semi-amplitude (K1)
(primary)		13.5 km/s
Details
Mass7.7±0.2 M☉
Radius5.72 R☉
Luminosity3,603 L☉
Surface gravity (log g)4.0 cgs
Temperature18,700 K
Rotational velocity (v sin i)25 km/s
Age32.0±0.4 Myr
Other designations
Furud, Phurud, ζ CMa, Zeta CMa, 1 Canis Majoris, CD−30°3038, FK5 240, GC 8170, HD 44402, HIP 30122, HR 2282, SAO 196698, WDS J06203-3004A
Database references
SIMBADdata

Zeta Canis Majoris is a binary star system in the southern constellation of Canis Major. Its name is a Bayer designation that is Latinized from ζ Canis Majoris; it has the proper name Furud, pronounced /ˈfjʊərəd/. This system has a combined apparent visual magnitude of +3.0, 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. It is drifting further away with a radial velocity of +32 km/s.

Name

ζ Canis Majoris, Latinized from Zeta Canis Majoris, is the star's Bayer designation assigned by the German astronomer Johann Bayer in 1603. It is abbreviated Zeta CMa or ζ CMa.

The traditional name Furud or Phurud derives from the Arabic ألفرود al-furūd "the solitary ones". This was an appellation 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.

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

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

Properties

A light curve for Zeta Canis Majoris, plotted from TESS data

The binary nature of this system was first noted by G. E. Paddock based on observations made in 1906 from the D. O. Mills Observatory in Chile. It was confirmed in 1909 by S. A. Mitchell, using radial velocity measurements made by F. E. Harpham in 1908. It 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.

The primary component has nearly eight times the mass of the Sun and 5.7 times the Sun's radius. It has a stellar classification of B2.5 V, which means it is a B-type main sequence star that is generating energy through the nuclear fusion of hydrogen at its core. Currently it is about 32 million years old. The star is emitting 3,600 times the luminosity of the Sun, radiating it from its photosphere at an effective temperature of about 18,700 K, giving it the blue-white hue of a B-type star. It was a suspected Beta Cephei variable, until observations with TESS led to its classification as a slowly pulsating B-type star.

Zeta Canis Majoris is located close to the solar antapex.

Notes

  1. 1 2 Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:

References

  1. 1 2 3 4 5 6 7 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, S2CID 18759600
  2. 1 2 3 4 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. 1 2 Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 3, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1982mcts.book.....H
  4. 1 2 Balona, L. A.; Ozuyar, D. (2020), "Pulsation among TESS a and B stars and the Maia variables", Monthly Notices of the Royal Astronomical Society, 493 (4): 5871, arXiv:2001.04497, Bibcode:2020MNRAS.493.5871B, doi:10.1093/mnras/staa670, S2CID 210472317.
  5. 1 2 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, vol. 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, S2CID 119257644.
  7. ↑ Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
  8. 1 2 Abt, Helmut A. (August 2005), "Observed Orbital Eccentricities", The Astrophysical Journal, 629 (1): 507–511, Bibcode:2005ApJ...629..507A, doi:10.1086/431207
  9. 1 2 3 4 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:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873
  10. 1 2 3 4 5 Hohle, M. M.; et al. (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, S2CID 111387483
  11. ↑ 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
  12. ↑ Abt, Helmut A.; et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  13. ↑ "zet CMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-02-15.
  14. ↑ Mamajek, Eric, IAU Catalog of Star Names, University of Rochester Department of Physics and Astronomy, retrieved 28 July 2016.
  15. ↑ 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.
  16. ↑ 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 December 12, 2010{{citation}}: CS1 maint: ignored ISBN errors (link)
  17. ↑ IAU Working Group on Star Names (WGSN), International Astronomical Union, archived from the original on 10 June 2016, retrieved 22 May 2016.
  18. ↑ Mamajek, Eric, Bulletin of the IAU Working Group on Star Names, No. 1 (PDF), University of Rochester Department of Physics and Astronomy, retrieved 28 July 2016.
  19. ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 11 July 2025.
  20. ↑ Curtis, H. D. (April 1909), "Five stars having variable radial velocities", Astrophysical Journal, 29: 229–231, Bibcode:1909ApJ....29..229C, doi:10.1086/141645.
  21. ↑ Mitchell, S. A. (October 1909), "Seven spectroscopic binaries", Astrophysical Journal, 30: 239–242, Bibcode:1909ApJ....30..239M, doi:10.1086/141699.
  22. ↑ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16
  23. ↑ 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, hdl:2066/36162