Gamma Velorum

Starbox begin
name=Gamma² Velorum A/B Starbox observe
epoch=J2000
ra=08^h 09^m 32.0^s
dec=−47° 20′ 12.0″
appmag_v=1.78/4.27
constell=Vela Starbox character
class=WC8 / O7.5e
b-v=−0.22
u-b=−0.99
variable=Wolf-Rayet Starbox astrometry
radial_v=35
prop_mo_ra=−5.93
prop_mo_dec=9.90
parallax=3.88
p_error=0.53
absmag_v=−5.31/−2.79 Starbox catalog
names=Regor, Suhail, Suhail Al-Muhlif, HR 3207, CD −46°3846/3847, HD 68273, SAO 219504, FK5 309, GC 11105, CCDM 08095-4721, HIP 39953. Starbox reference
Simbad=HD+68273

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 Al Suhail al-Muhlif (confusingly, the name "Suhail" can also apply to other stars such as 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. [Apollo 15 Lunar Surface Journal, [http://history.nasa.gov/alsj/a15/a15.postland.html "Post-landing Activities"] , commentary at 105:11:33] 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. [cite web | author=Hoffleit| url=http://www.alcyone.de/SIT/mainstars/SIT000822.htm#Cat1| title=The Bright Star Catalogue, 5th Revised Ed.| accessdate = 2007-08-08] 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.

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".

References

External links

* [http://www.astro.uiuc.edu/~kaler/sow/regor.html Regor] by Jim Kaler, Professor Emeritus of Astronomy, University of Illinois at Urbana-Champaign
* [http://www.space.com/spacewatch/star_names_030829.html NightSky Friday: Rotanev, Derf, Navi, and other Backward Star Names] – Space.com article
* [http://www.starrynightphotos.com/southern_sky/gamma_vela.htm Starry Night Photography: Gamma Velorum]