Sigma Canis Majoris

σ Canis Majoris
Location of σ Canis Majoris (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Canis Major
Right ascension 07h 01m 43.14779s[1]
Declination −27° 56′ 05.3898″[1]
Apparent magnitude (V) 3.43 - 3.51[2]
Characteristics
Spectral type K5 Ib[3]
U−B color index +1.88[4]
B−V color index +1.73[4]
Variable type LC[2]
Astrometry
Radial velocity (Rv)+22.11[5] km/s
Proper motion (μ) RA: −3.047[6] mas/yr
Dec.: +4.08[6] mas/yr
Parallax (π)2.5085 ± 0.1590 mas[7]
Distance1290+76
−80 ly
(395.6+23.2
−24.4 pc)[8]
Absolute magnitude (MV)−5.14[9]
Details
Mass5.61+0.51
−0.49,[10] 8.4±1.0, 9.1±2.0[11] M☉
Radius297[12] R☉
Luminosity15,800[12] L☉
Surface gravity (log g)0.32[10] cgs
Temperature3792±125[11] K
Metallicity [Fe/H]+0.16[13] dex
Age83.2[10] Myr
Other designations
Unurgunite, 22 Canis Majoris, ADS 5719, CD−27°3544, FK5 1183, HD 52877, HIP 33856, HR 2646, SAO 172797.[14]
Database references
SIMBADdata

Sigma Canis Majoris (σ Canis Majoris, abbreviated Sigma CMa, σ CMa), also named Unurgunite /ˌʌnərˈɡʌnaɪt/,[15] is a variable star in the southern constellation of Canis Major. It is approximately 1,290 light-years (400 parsecs) from the Sun and has an average apparent visual magnitude of +3.41.

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