mercredi 3 septembre 2008

Argo Navis 4 Carina


Avior


Epsilon Carinae

Distance (Light Years)
630 ± 60
Visual Magnitude
1.86
Color (B-V)
1.28
Names For This StarAccording to Lynne Marie Stockman, the name "Avior" is a coinage of Great Britain's H. M. Nautical Almanac Office. See HMNAO Star Names for the story.
Description of the StarThe spectrum of Avior is a composite spectrum characteristic of a K3III giant and a B2V main sequence star. The giant would be an orange star with an effective temperature of 4100 K, a mass of about 4.6 times that of the sun, and a diameter about 20 times that of the sun. The spectral type implies a luminosity about 110 times that of the sun.
The main sequence companion would be much hotter at a temperature of 23,000 K. The spectral type implies a diameter of 6 times that of the sun, a mass of 16 times that of the sun, and a luminosity of 8800 times that of the sun. The luminosity of the system must be mainly due to this star, which is measured to be 1.96 magnitudes brighter than the giant.
The Hipparcos Catalogue mission found a separation 0.463 arc seconds between the two stars, corresponding to a projected distance of 90 AU between the stars. This distance is about 2.25 times the radius of the solar system out to Pluto.



Canopus
Alpha Carinae


Distance (Light Years)
313± 16
Visual Magnitude
-0.62
Color (B-V)
0.15
Names For This StarOther names for this star are Suhel or Suhail. (Note that Lambda Velorum also bears the name "Suhail;" according to Allen bright stars were often given the name "Suhail" by Arab skywatchers.)
Allen offers at least two origins for "Canopus." One etymology traces the name of the star to the chief pilot of the Greek fleet in the war against Troy written of by Homer. Legend connects the city of Canopus in Egypt with the pilot and the star. The story is that Canopus' ship landed in Egypt as the Greeks sailed home after destroying Troy. King Menelaos then built a monument to the pilot at that site and named the city after him, as well as the star.
Allen thinks it more likely that the name derives from phrase in the Coptic language, Kahi Nub meaning "Golden Earth." The Coptic name would refer to the brightness of the star and its very low altitude above the horizon - less than 8° on the northern coast of Egypt.
Description of the StarCanopus is a yellowish F0II bright giant having 65 times the diameter of the sun and 14,000 times the luminosity.
Canopus is the second brightest star in the nighttime sky. Sirius at Visual Magnitude -1.44 is the only star exceeding Canopus in brightness.
Canopus is visible only from the southern half of the United States and there at only a very low altitude during the winter months. Burnham calls the star The Great Star of the South, and indeed, the more southerly your location, the better will you be able to see the star.



Miaplacidus



Beta Carinae



Distance (Light Years)
111.2 ± 1.8
Visual Magnitude
1.67
Color (B-V)
0
Names For This StarAllen suggests that the name of the star is connected with the Arabic word Mi'ah meaning "Waters." The latter part of the name, -placidus, is clearly Latin and means "placid". This suggests that the name of the star should be translated as "Placid Waters." See "Dolan2" and "Gibson".
Description of the StarMiaplacidus is a hot, white A2IV subgiant star having a luminosity of about 210 times that of the sun and a diameter about 5.7 times greater than the sun.

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