Nu1 Canis Majoris
Binary star system in the constellation Canis Major
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Nu1 Canis Majoris is a binary star in the constellation Canis Major. Its name is a Bayer designation that is Latinized from ν1 Canis Majoris, and abbreviated Nu1 CMa or ν1 CMa. This system is visible to the naked eye as a point of light with an apparent visual magnitude of 5.7.[2] Based on parallax shift of 12.366 mas as seen from Earth orbit,[1] this system is approximately 264 light years from the Sun. It is drifting further away with a line of sight velocity of +26 km/s.[2]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 36m 22.848s[1] |
| Declination | −18° 39′ 35.73″[1] |
| Apparent magnitude (V) | 5.704[2] (5.87 + 7.61)[3] |
| Characteristics | |
| Spectral type | G8 III + F3 IV-V[3] |
| B−V color index | +0.815[2] |
| Astrometry | |
| Radial velocity (Rv) | +26.13[2] km/s |
| Proper motion (μ) | RA: −9.902 mas/yr[1] Dec.: +23.229 mas/yr[1] |
| Parallax (π) | 12.3660±0.1985 mas[1] |
| Distance | 264 ± 4 ly (81 ± 1 pc) |
| Absolute magnitude (MV) | +1.23[4] |
| Details | |
| ν1 CMa A | |
| Mass | 1.41[2] M☉ |
| Radius | 7.1±0.3[1] R☉ |
| Luminosity | 8[2] L☉ |
| Surface gravity (log g) | 3.00[5] cgs |
| Temperature | 6,091±822[2] K |
| Metallicity [Fe/H] | −0.06[5] dex |
| Rotational velocity (v sin i) | 4.8±0.2[4] km/s |
| Age | 3.07[2] Gyr |
| Other designations | |
| ν1 CMa, 6 Canis Majoris, BD−18°1480, GC 8614, HD 47138, HIP 31564, HR 2423, SAO 151694, ADS 5253, CCDM 06364-1840, WDS 06364-1840[6] | |
| Database references | |
| SIMBAD | data |
As of 2011, the pair had an angular separation of 17.29 arc seconds along a position angle of 264.2°.[7] The yellow hued magnitude 5.87[3] primary, component A, is an evolved G-type giant star with a stellar classification of G8 III.[3] It is an estimated 3[2] billion years old and has 1.4[2] times the mass of the Sun. Having exhausted the supply of hydrogen at its core, it has expanded to 7 times the Sun's radius[1] and is radiating 8 times the luminosity of the Sun from its photosphere at an effective temperature of 6,091 K.[2]
The magnitude 7.61[3] companion, component B, is a yellow-white hued F-type main sequence/subgiant hybrid with a class of F3 IV-V.[3]