Lambda Canis Majoris

Lambda Canis Majoris is a solitary,^[8] blue-white hued star in the constellation Canis Major. Its name is a Bayer designation that is Latinized from λ Canis Majoris, and abbreviated Lambda CMa or λ CMa. This star is visible to the naked eye with an apparent visual magnitude of +4.48.^[2] Based upon an annual parallax shift of 7.41 mas as seen from Earth,^[1] it is located about 440 light-years (135 pc) away from the Sun. At that distance, the visual magnitude is diminished by an extinction of 0.14 due to interstellar dust.^[5] It is receding from the Sun with a line of sight velocity of +41 km/s.^[4]

Lambda Canis Majoris

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Canis Major
Right ascension	06h 28m 10.208s[1]
Declination	−32° 34′ 48.25″[1]
Apparent magnitude (V)	+4.48[2]
Characteristics
Spectral type	B4 V[3]
U−B color index	−0.61[2]
B−V color index	−0.17[2]
Astrometry
Radial velocity (Rv)	+41.0±4.1[4] km/s
Proper motion (μ)	RA: −13.777 mas/yr[1] Dec.: +25.459 mas/yr[1]
Parallax (π)	7.4077±0.1071 mas[1]
Distance	440 ± 6 ly (135 ± 2 pc)
Absolute magnitude (MV)	−0.85[5]
Details
Mass	4.98±0.05[1] M☉
Radius	4.30±0.07[1] R☉
Luminosity	824±22[1] L☉
Surface gravity (log g)	3.87±0.01[1] cgs
Temperature	15,481±22[1] K
Rotational velocity (v sin i)	102±9[3] km/s
Age	39.8±19.1[6] Myr
Other designations
λ CMa, CD−32°3066, GC 8410, HD 45813, HIP 30788, HR 2361, SAO 196857[7]
Database references
SIMBAD	data

This is a B-type main-sequence star with a stellar classification of B4 V.^[3] The star is roughly 40 million years old,^[6] and has a high rate of spin with a projected rotational velocity of 102 km/s.^[3] It has about 5 times the mass of the Sun and 4.3 times the Sun's radius. The star is radiating 824 times the Sun's luminosity at an effective temperature of 15,481 K.^[1]