R Canis Majoris
| Observation data Epoch J2000.0 Equinox | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 07h 19m 28.18202s |
| Declination | −16° 23′ 42.8773″ |
| Apparent magnitude (V) | 5.70 - 6.34 |
| Characteristics | |
| Spectral type | F0V + G8IV |
| U−B color index | +0.01 |
| B−V color index | +0.34 |
| Variable type | Algol |
| Astrometry | |
| Radial velocity (Rv) | −39.0 km/s |
| Proper motion (μ) | RA: +165.37 mas/yr Dec.: −136.18 mas/yr |
| Parallax (π) | 23.38±0.54 mas |
| Distance | 140 ± 3 ly (42.8 ± 1.0 pc) |
| Absolute magnitude (MV) | +2.57 |
| Details | |
| primary | |
| Mass | 1.67 M☉ |
| Radius | 1.78 R☉ |
| Luminosity | 8.2 L☉ |
| Surface gravity (log g) | 4.16 cgs |
| Temperature | 7,300 K |
| Rotational velocity (v sin i) | 78.3±3.9 km/s |
| secondary | |
| Mass | 0.22 M☉ |
| Radius | 1.22 R☉ |
| Luminosity | 0.49 L☉ |
| Surface gravity (log g) | 3.60 cgs |
| Temperature | 4,350 K |
| tertiary | |
| Mass | 0.8 M☉ |
| Radius | 0.83 R☉ |
| Luminosity | 0.4 L☉ |
| Surface gravity (log g) | 4.50 cgs |
| Other designations | |
| R Canis Majoris, BD−16°1898, HR 2788, HD 57167, HIP 35487, SAO 152724, GC 9758 | |
| Database references | |
| SIMBAD | data |
R Canis Majoris is an eclipsing interacting binary star system in the constellation Canis Major. It varies from magnitude 5.7 to 6.34. The system is unusual in the low mass ratio (ie. big mass difference) between the main two components and shortness of the orbital period. It is faintly visible to the naked eye of an observer with very good observing conditions.