EZ Canis Majoris

EZ Canis Majoris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension 06h 54m 13.0441s[1]
Declination −23° 55′ 42.011″[1]
Apparent magnitude (V) 6.71 to 6.95[2]
Characteristics
Spectral type WN4[1]
U−B color index −0.89[3]
B−V color index −0.28[3]
R−I color index +0.06[3]
Variable type WR[2]
Astrometry
Proper motion (μ) RA: −3.86[1] mas/yr
Dec.: 4.75[1] mas/yr
Parallax (π)1.74 ± 0.76[1] mas
Distance5,900 ly
(1,800[4] pc)
Absolute magnitude (MV)−4.6[4]
Details
Mass20[5] M☉
Radius2.9[4] R☉
Luminosity (bolometric)380,000[4] L☉
Temperature85,000[4] K
Other designations
EZ CMa, ALS 98, CD−23°4553, CEL 1426, Collinder 121 4, CPD−23°1588, GC 9061, HD 50896, Hen 3-20, HIP 33165, HR 2583, LBN 1052, LMA IC 1613 10, MR 6, PPM 251223, SAO 172546, SH 2-308, TYC 6522-3270-1.[1]
Database references
SIMBADdata

EZ Canis Majoris (EZ CMa) is a Wolf-Rayet star in the constellation of Canis Major.[1] It has an apparent visual magnitude which varies between 6.71 and 6.95,[2] over a period of 3.766 days.[6] It is the sixth-brightest Wolf-Rayet star.[6]

EZ Canis Majoris shows variations on its spectrum with a period of approximately 3.8 days and it has been proposed it could be a binary star, with a neutron star as companion that would complete an orbit around the Wolf-Rayet with that period, being it the cause of those variations; however it seems more likely that companion does not exist and spectral variations are caused by activity on the star's surface.[6]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 V* EZ CMa -- Wolf-Rayet Star, database entry, SIMBAD. Accessed on line November 20, 2008.
  2. ↑ 2.0 2.1 2.2 EZ CMa, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line November 20, 2008.
  3. ↑ 3.0 3.1 3.2 HR 2583, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 20, 2008.
  4. ↑ 4.0 4.1 4.2 4.3 4.4 Spitzer Space Telescope Infrared Spectrograph (IRS) Spectroscopy of the Prototype Wolf-Rayet Star EZ Canis Majoris (HD 50896), Patrick W. Morris, Paul A. Crowther, and Jim R. Houck, Astrophysical Journal Supplement Series 154, #1 (September 2004), pp. 413–417, doi:10.1086/422878, Bibcode: 2004ApJS..154..413M. Stellar parameters are in Table 1.
  5. ↑ §6, Photon loss from the helium Lyα line — the key to the acceleration of Wolf-Rayet winds, W. Schmutz, Astronomy and Astrophysics 321 (May 1997), pp. 268–287, Bibcode: 1997A&A...321..268S.
  6. ↑ 6.0 6.1 6.2 The IUE Mega Campaign: Wind Structure and Variability of HD 50896 (WN5) Astrophysical Journal Letters 452 #1, pp. L57 (October 1995) Bibcode: 1995ApJ...452L..57S