Achernar

From Free net encyclopedia

This article is about the star Achernar. For the character in the Myst series, see Achenar (Myst).

Template:Starbox begin Template:Starbox image Template:Starbox observe Template:Starbox character Template:Starbox astrometry Template:Starbox detail Template:Starbox catalog Template:Starbox end Achernar (α Eri / α Eridani / Alpha Eridani) is the brightest star in the constellation Eridanus and the ninth brightest star in the nighttime sky. It lies at the southern tip of the constellation.

Achernar is a bright supergiant star of six to eight solar masses. It is visible in the southern part of the night sky. It remains permanently below the horizon from many densely populated portions of Earth's northern hemisphere. From those Southern hemisphere countries from which it can be seen best, it is particularly conspicuous through being highest in the night sky in November when most other bright southern stars are skirting the horizon.

Until about March 2000, Achernar and Fomalhaut were the two first magnitude stars furthest in angular distance from any other first magnitude star in the celestial sphere. Antares, in the constellation of Scorpius, is now the most isolated first magnitude star.

It is the least spherical star in the Milky Way studied to date. Achernar spins so rapidly that its equatorial diameter is more than 50% greater than its polar diameter.

It is approximately 144 light years from the Solar System.

The name comes from the Arabic آخر النهر ākhir an-nahr "river's end".

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Fiction

Achenar is the seat of the Emperor in computer game Elite
In the Myst games, a character named Achenar appears. (His brother Sirrus was probably named after Sirius.)

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