GAMMA VELORUM

'Gamma Velorum' (γ Vel / γ Velorum) is a star system in the constellation Vela. At magnitude +1.7, it is one of the brightest stars in the nighttime sky. It has the traditional names 'Suhail' or 'Suhail Al‐Muhlif', and a more modern popular name of 'Regor', which was invented as a practical joke by the Apollo 1 astronaut Gus Grissom for his fellow astronaut Roger Chaffee. Due to the exotic nature of its spectrum (bright emission lines in lieu of dark absorption lines) it is also dubbed the 'Spectral Gem of Southern Skies'.^[1] Confusingly, however, the name ''Suhail'' can also apply to other stars such as Lambda Velorum.
The Gamma Velorum system is composed of at least six stars. The brightest member, 'γ² Velorum' or 'γ Velorum A', is actually a spectroscopic binary composed of a blue supergiant of spectral class O9 (30 M_☉), and a massive Wolf-Rayet star, the heaviest known (10 M_☉, originally approx. 40 M_☉). The binary has an orbital period of 78.5 days and separation of 1 AU. Its nearest companion, the bright (apparent magnitude +4.2) 'γ¹ Velorum' or 'γ Velorum B', is a blue-white B-type subgiant. It is separated from the Wolf-Rayet binary by 41.2", and the separation can easily be resolved with binoculars.
Gamma Velorum has several fainter companions. The magnitude +8.5 'γ Velorum C', a white A-type star, is 62.3 arcseconds from the A component. At 93.5 arcseconds is the system's second binary star, 'γ Velorum D' and 'E'. The D component is another A-type star which has a magnitude of +9.4. Its companion is a 13th magnitude star, separated by 1.8 arcseconds.

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External links

References

1. The Bright Star Catalogue, 5th Revised Ed. Hoffleit

External links

★ Regor by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois at Urbana-Champaign

★ NightSky Friday: Rotanev, Derf, Navi, and other Backward Star Names – Space.com article

★ Starry Night Photography: Gamma Velorum