Theta Canis Majoris (θ Canis Majoris) is a solitary,[7] orange-hued star near the northern edge[8] of the constellation Canis Major, forming the nose of the "dog".[9] The star is visible to the naked eye with an apparent visual magnitude of 4.08.[2] Based upon an annual parallax shift of 12.51 mas as seen from Earth,[1] it is located about 260 light years from the Sun. The star is moving away from us with a radial velocity of +96.2 km/s.[4]

Theta Canis Majoris

Location of θ Canis Majoris (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Canis Major
Right ascension	06h 54m 11.39877s[1]
Declination	−12° 02′ 19.0674″[1]
Apparent magnitude (V)	4.08[2]
Characteristics
Spectral type	K4 III[2]
U−B color index	+1.69[3]
B−V color index	+1.43[3]
Astrometry
Radial velocity (Rv)	+96.2±0.1[4] km/s
Proper motion (μ)	RA: −137.26[1] mas/yr Dec.: −15.37[1] mas/yr
Parallax (π)	12.51 ± 0.62 mas[1]
Distance	260 ± 10 ly (80 ± 4 pc)
Absolute magnitude (MV)	−0.36±0.15[5]
Details[4]
Mass	0.95±0.03 M☉
Radius	31.91±1.92 R☉
Luminosity	263 L☉
Surface gravity (log g)	1.67±0.08 cgs
Temperature	4,145±26 K
Metallicity [Fe/H]	−0.52±0.04 dex
Rotational velocity (v sin i)	2.72±0.40 km/s
Age	10.41±1.31 Gyr
Other designations
θ CMa, 14 Canis Majoris, BD−11°1681, FK5 266, GC 9051, HD 50778, HIP 33160, HR 2574, SAO 152071[6]
Database references
SIMBAD	data

This is an old, evolved K-type giant star with a stellar classification of K4 III.[2] It is about ten billion years old with 0.95 times the mass of the Sun, but has expanded to 32 times the Sun's radius. The star is radiating 263 times the Sun's luminosity from its photosphere at an effective temperature of 4,145 K.[4]

References

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