vendredi 19 septembre 2008

Eridanus 7

The chair

Beta Eridani (Beta Eri / β Eridani / β Eri) is the second brightest star in the constellation of Eridanus, located in the northeast end of this constellation. It also has the traditional names Cursa and Dhalim.

Theta Eridani (θ Eri / θ Eridani) est une étoile dans la constellation de l'Éridan. Elle est également appelée par son nom traditionnel Acamar (de l'arabe آخر النهر, ʼĀkhir ān-nahr, signifiant « l'embouchure de la rivière » ; avec l'alphabet latin, le « m » peut se confondre avec « rn »). Il est connu comme 天园六 (« la sixième étoile du verger céleste ») en Chine.
Acamar est une étoile double, dont la séparation angulaire des deux étoiles s'élève à 8,2".
Ptolémée l'a décrite comme une étoile de première magnitude ; Al-Soufi l'a classée dans les 30 étoiles les plus brillantes du ciel aux alentours du Xe siècle ; Ulugh Beg l'a également répertoriée comme une étoile de première magnitude au XVe siècle.

Gamma Eridani (γ Eri / γ Eridani) est une étoile de la constellation de l'Éridan. Elle porte également le nom traditionnel Zaurak, qui signifie "le bateau", de l'arabe الزورق Az-Zawraq.
Zaurak a une magnitude apparente de +2,95 et est de type spectral M0.5IIICa-ICr -. Elle est à environ 220 années-lumière de la Terre.

Delta Eridani (δ Eri / δ Eridani) is a 3.54 magnitude star in the constellation of Eridanus. It is also called Rana.
This star is relatively near to the Sun, at a measured distance of about 29 light years. It is sometime listed as a RS Canum Venaticorum-type variable star, but this is likely to be an error. (It is currently a suspected variable.) Rana is a sub-giant star that is near the end of its hydrogen-burning cycle and is now consuming helium. This has caused the star to expand and become hotter than a comparable main sequence star. As a sub-giant star it is subject to pulsations in its atmosphere.
Radial velocity surveys of this star have thus far failed to discern any gas giants in orbit.
The name Rana means "the frog" in Latin, and was apparently transferred in the 20th century from another star, Deneb Kaitos, which was also called "Rana Secunda", or second frog.

Tau4 Eridani (τ4 Eri / τ4 Eri) is a Class M3.5III, fourth-magnitude star in the constellation Eridanus. It has the seldom used proper name Liberfluus (Liberflux), which is Latin and means "Free-flowing" River.
Tau4 Eridani is a binary star system consisting primarily of Class M components, the brightest component being a Class M giant of apparent magnitude 3.66, having a mass and luminosity many times greater than that of the Sun. It is occasionally eclipsed by other stellar components within the system in ways similar to Algol. The entire star system is located about 260 light-years from Earth.

Eta Eridani (η Eri / η Eridani) is a star in the constellation Eridanus. It also has the traditional name Azha ("the breeding place"). The word Azha is a corruption of Persian آشيانه āšiyāne The (ostrich) nest.
Eta Eridani belongs to spectral class K0 and has apparent magnitude +4.1. It is 121 light years from Earth.

The eggs

Omicron-1 Eridani (aka Beid) is a star of visual magnitude 4.04.[1] It lies approximately 125 light-years from Earth in the Eridanus constellation and is a class F (F2) giant with a temperature of 7100 kelvins and a luminosity 28 times that of the Sun. In 1971 it was discovered to be a Delta Scuti variable star, with a variation of just a few hundredths of a magnitude with periods of 1.8 and 3.5 days.

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