Gamma Velorum
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| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Vela |
| Right ascension | 08h 09m 32.0s |
| Declination | −47° 20′ 12.0″ |
| Apparent magnitude (V) | 1.78/4.27 |
| Characteristics | |
| Spectral type | WC8 / O7.5e |
| U-B color index | −0.99 |
| B-V color index | −0.22 |
| Variable type | Wolf-Rayet |
| Astrometry | |
| Radial velocity (Rv) | 35 km/s |
| Proper motion (μ) | RA: −5.93 mas/yr Dec.: 9.90 mas/yr |
| Parallax (π) | 3.88 ± 0.53 mas |
| Distance | approx. 800 ly (approx. 260 pc) |
| Absolute magnitude (MV) | −5.31/−2.79 |
| Other designations | |
| Database references | |
| SIMBAD | data |
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 and Suhail al Muhlif, which confusingly also apply to Lambda Velorum. It also has a more modern popular name Regor, which was invented as a practical joke by the Apollo 1 astronaut Gus Grissom for his fellow astronaut Roger Chaffee.[1] 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.[2] 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.
[edit] Etymology
The medieval name Suhail (Al Suhail, Alsuhail, Suhail al Muhlif, Muliphein) is short for the Arabic سهيل المحلف suhayl al-muħlif "The glorious (star) of the oath".
[edit] References
- ^ Apollo 15 Lunar Surface Journal, Post-landing Activities, commentary at 105:11:33
- ^ Hoffleit. "The Bright Star Catalogue, 5th Revised Ed.". http://www.alcyone.de/SIT/mainstars/SIT000822.htm#Cat1. Retrieved 2007-08-08.
[edit] 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
