Nu1 Canis Majoris

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]

For other stars with this Bayer designation, see ν Canis Majoris.

Nu¹ Canis Majoris

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]