Beta Canis Majoris
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 22m 41.98535s |
| Declination | −17° 57′ 21.3073″ |
| Apparent magnitude (V) | 1.985 (1.97 – 2.01) |
| Characteristics | |
| Spectral type | B1 II-III |
| U−B color index | −0.99 |
| B−V color index | −0.235 |
| Variable type | β Cep |
| Astrometry | |
| Radial velocity (Rv) | +33.7 km/s |
| Proper motion (μ) | RA: −3.23 mas/yr Dec.: −0.78 mas/yr |
| Parallax (π) | 6.62±0.22 mas |
| Distance | 490 ± 20 ly (151 ± 5 pc) |
| Absolute magnitude (MV) | −3.93±0.04 |
| Details | |
| Mass | 13±1 M☉ |
| Radius | 8.44±0.56 R☉ |
| Luminosity | 25,700+3,800 −3,300 L☉ |
| Surface gravity (log g) | 3.70±0.08 cgs |
| Temperature | 25,180±1,120 K |
| Metallicity [Fe/H] | 0.04±0.10 dex |
| Rotation | 13.6±1.2 days |
| Rotational velocity (v sin i) | 31±5 km/s |
| Age | 12.2 or 13.8 Myr |
| Other designations | |
| Mirzam, Murzim, Mirza, β Canis Majoris, 2 Canis Majoris, BD−17°1467, FK5 243, GC 8223, HD 44743, HIP 30324, HR 2294, SAO 151428, CCDM 06227-1757 | |
| Database references | |
| SIMBAD | data |
Beta Canis Majoris is a star in the southern constellation of Canis Major, the "Great Dog". Its name is a Bayer designation; it has the proper name Mirzam, pronounced /ˈmɜːrzəm/. Visible to the naked eye, this is a variable star that ranges in apparent visual magnitude from 1.97 to 2.01 over a period of six hours. Based on parallax measurements, it is located at a distance of about 500 light-years (150 parsecs) from the Earth. The star is drifting further away from the Sun with a line of sight velocity of +34 km/s. In the modern constellation it lies at the position of the dog's front leg.