EZ Canis Majoris
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) |
|
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 54m 13.04410s[1] |
| Declination | −23° 55′ 42.0150″[1] |
| Apparent magnitude (V) | 6.91[2] 6.71 to 6.95[3] |
| Characteristics | |
| Spectral type | WN4-s[4] |
| U−B color index | −0.89[2] |
| B−V color index | −0.28[2] |
| Variable type | UGZ?[3] |
| Astrometry | |
| Proper motion (μ) | RA: −3.76[1] mas/yr Dec.: 4.35[1] mas/yr |
| Parallax (π) | 0.72 ± 0.62[1] mas |
| Distance | 4,900 ly (1,500[5] pc) |
| Absolute magnitude (MV) | −4.85[4] |
| Details | |
| Mass | 19[4] M☉ |
| Radius | 2.65[4] R☉ |
| Luminosity (bolometric) | 400,000[4] L☉ |
| Temperature | 89,100[4] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
EZ Canis Majoris (EZ CMa) is a Wolf-Rayet star in the constellation of Canis Major. It is one of the ten brightest Wolf-Rayet stars.[6]
EZ CMa has an apparent visual magnitude which varies between 6.71 and 6.95 over a period of 3.766 days, along with changes in the spectrum.[7] It has been proposed that 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. The General Catalogue of Variable Stars lists it as a possible cataclysmic variable on this basis. However it seems more likely that companion does not exist and spectral variations are caused by activity on the star's surface.[7]
The spectral type of WN4 indicates an extremely hot star, and this leads to a very high luminosity, mostly emitted as ultraviolet radiation. The spectrum shows a star entirely devoid of hydrogen at the surface.[4]
EZ CMa is surrounded by a faint bubble nebula, a small HII region blown by stellar winds up to 1,700 km/s and ionised by the intense UV radiation.[5]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 3.0 3.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ 7.0 7.1 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
