Mu Canis Majoris (μ Canis Majoris) is a binary star[2] system in the southern constellation of Canis Major. The pair can be located a little to the southwest of the point midway between Gamma and Theta Canis Majoris,[11] and the components can be split with a small telescope.[12] The system is faintly visible to the naked eye with an apparent visual magnitude of 5.12.[2] Based upon an annual parallax shift of just 2.62 mas as seen from Earth,[1] this system is located roughly 1,200 light years from the Sun.
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Canis Major |
Right ascension | 06h 56m 06.64589s[1] |
Declination | −14° 02′ 36.3520″[1] |
Apparent magnitude (V) | 5.12 (5.27 + 7.32)[2] |
Characteristics | |
Spectral type | K2/3 III + B9/A0 V[3] |
Astrometry | |
Radial velocity (Rv) | 18.1±0.1[4] km/s |
Proper motion (μ) | RA: −1.59[1] mas/yr Dec.: + 6.33[1] mas/yr |
Parallax (π) | 2.62 ± 0.58 mas[1] |
Distance | approx. 1,200 ly (approx. 380 pc) |
Absolute magnitude (MV) | −2.22[5] |
Details | |
μ CMa A | |
Surface gravity (log g) | 2489[6] cgs |
Temperature | 4,441[6] K |
Rotational velocity (v sin i) | ≤ 5[7] km/s |
μ CMa B | |
Mass | 14.7±0.3[8] M☉ |
Age | 11.6±0.5[8] Myr |
Other designations | |
μ CMa A: HD 51250[9] | |
μ CMa B: HD 51251[10] | |
Database references | |
SIMBAD | data |
Grotius assigned the name Isis to this star, but the name, now obsolete, belonged rather to Gamma Canis Majoris.[13]
As of 2011, the pair had an angular separation of 2.77 arc seconds along a position angle of 343.9°.[14] The orange-hued primary member, component A, is an evolved K-type giant star with a stellar classification of K2/3 III[3] and a visual magnitude of 5.27.[2] The base magnitude 7.32[2] companion, component B, is a hybrid B/A-type main-sequence star with a class of B9/A0 V.[3]
The system has two visual companions. As of 2008, magnitude 10.32 component C lies at an angular separation of 86.90″, while magnitude 10.64 component D is at a separation of 105.0″.[15] Mu CMa should not be confused with the 9th magnitude variable star MU CMa located near NGC 2360.[16]
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