Gamma Velorum

γ2 Velorum
Location of γ Velorum (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 08h 09m 31.95013s
Declination –47° 20 11.7108
Apparent magnitude (V) 1.83 (1.81–1.87)
Characteristics
Spectral type WC8 + O7.5III
U−B color index −0.94
B−V color index −0.25
Variable type Wolf–Rayet
Astrometry
Radial velocity (Rv)+12±1 km/s
Proper motion (μ) RA: –6.07 mas/yr
Dec.: +10.43 mas/yr
Parallax (π)2.92±0.30 mas
Distance1096+26
−23
 ly
(336+8
−7
 pc)
Absolute magnitude (MV)−4.6 + −6.0
Orbit
PrimaryO
CompanionWR
Period (P)78.53±0.01 days
Semi-major axis (a)1.2 AU
Eccentricity (e)0.326±0.01
Inclination (i)65±8°
Periastron epoch (T)2,450,120.5±2
Argument of periastron (ω)
(secondary)
248±4°
Semi-amplitude (K1)
(primary)
38.4±2 km/s
Semi-amplitude (K2)
(secondary)
122±2 km/s
Details
WR
Mass9.0±0.6 M
Radius1.9 R
Luminosity (bolometric)204,000 L
Luminosity (visual, LV)5,900 L
Temperature90,000 K
Age5 Myr
O
Mass28.5±1.1 M
Radius16.2 R
Luminosity (bolometric)363,000 L
Luminosity (visual, LV)21,500 L
Temperature35,100 K
Age5 Myr
Other designations
Regor, Suhail Al-Muhlif, CD−46°3847, FK5 309, HD 68273, HIP 39953, HR 3207, SAO 219504, WR 11
Database references
SIMBADdata

Gamma Velorum is a quadruple star system in the constellation Vela. This name is the Bayer designation for the star, which is Latinised from γ Velorum and abbreviated γ Vel. At a combined magnitude of +1.72, it is one of the brightest stars in the night sky, and contains by far the closest and brightest Wolf–Rayet star. It has the traditional name Suhail al Muhlif and the modern name Regor /ˈrɡɔːr/, but neither is approved by the International Astronomical Union, making it the brightest star by apparent magnitude without an IAU approved name.

The γ Velorum system includes a pair of stars separated by 41, each of which is also a spectroscopic binary system. γ2 Velorum, the brighter of the visible pair, contains the Wolf–Rayet star and a blue supergiant, while γ1 Velorum contains a blue giant and an unseen companion.