mercredi 3 septembre 2008

Argo Navis 13, Vela


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.[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.



Alsuhail
Suhail
Un-translated
الشّولة


δ Velorum is a star system in the constellation Vela. It is approximately 79.7 light years from Earth. It is sometimes given the name Koo She, Chinese for 'Bow and Arrows', along with ω Velorum and stars in Canis Major.[1]
The system is composed of two binary stars. The brightest of the four stars, δ Velorum A, is a white A-type main sequence dwarf with an apparent magnitude of +2.02. Its binary companion, δ Velorum B, has a magnitude of +5.1 and is separated from the A component by 2.6 arcseconds.
The second binary system is 69 arcseconds away. It is composed of the 11th magnitude δ Velorum C and the 13th magnitude δ Velorum D, which are 6 arcseconds apart.
This star was recently discovered to be variable by the Galileo spaceprobe at Jupiter. [1] It fluctuates by about 30% every 45 days. Curiously, being one of the brighter stars in the sky, this had not been noticed previously.
Because of precession, δ Velorum will be the South Polar Star around 9000 AD.


λ Velorum is a star in the constellation Vela. It also has the traditional name Suhail (which, confusingly, is sometimes used for Gamma Velorum).
Lambda Velorum is a supergiant or bright giant star of spectral class K5. Supergiant stars use up their hydrogen "fuel" much faster than do smaller stars and λ Velorum is estimated to be only some 27 million years old. It is classified as an irregular variable star and its brightness varies from magnitude +2.14 to +2.30.



κ Velorum is a binary star in the constellation Vela. It also has the traditional name Markab, a name it shares with the star Alpha Pegasi.
Kappa Velorum is spectroscopic binary which is classified as a blue-white B-type subgiant with an apparent magnitude of +2.47. It is approximately 539 light years from Earth. The two components complete one orbit every 116.65 days.
The star is only a couple of degrees from the south celestial pole of Mars, so it could therefore be considered the southern polar star of Mars. Due to precession of the equinoxes, it will be the closest bright star of note to the south celestial pole of Earth in the period surrounding 9000 AD.

Markab
Mankib al-Faras
"The shoulder" of the horse
منكب الفرس


μ Velorum is a binary star in the constellation Vela. It is approximately 116 light years from Earth. Mu Velorum is approximately 38 solar diameters almost as big as Aldebaran
The primary component, Mu Velorum A, is a yellow G-type giant with an apparent magnitude of +2.69. The companion is a yellow G-type main sequence dwarf with an apparent magnitude of +6.6. The two stars are 0.7 arcseconds apart and complete one orbit every 116.24 years.
Peregrini.


φ Velorum ist ein Stern im Sternbild Segel des Schiffs.
Der Chinesen nannten ihn Tiānjì (天紀 - auch als Tseen Kee transkribiert), was übersetzt „Himmelsaufzeichnung“ bedeutet.

ο Velorum is a star in the constellation Vela. It has the proper name Xestus (Greek Ξηστως Xestos), which was the name of the god of sea currents and ocean currents who helped to guide the Argo on its journey.
Omicron Velorum is a blue-white B-type subgiant with a mean apparent magnitude of +3.60. It is approximately 495 light years from Earth. It is a variable star and its brightness varies from magnitude +3.55 to +3.67 with a period of 2.78 days.

Aucun commentaire: