Achernar
From Freepedia
- This article is about the star Achernar. For the character in the Myst series, see Achenar (Myst).
Image:Position Alpha Eri.png
Achernar (α Eri / α Eridani / Alpha Eridani) is the brightest star in the constellation Eridanus and the ninth brightest star in the nighttime sky.
Achernar is a bright supergiant star 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.
Archernar was, until March 2000, further in angular distance from any other 1st magnitude star in the sky than any other 1st magnitude star, along with Fomalhaut. That honour has now been taken by the star Antares in the constellation of Scorpius.
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 āxir an-nahr "end of the river".
Facts
- Apparent Visual Brightness (Sirius A = 1): 0.175
- Spectral type: B3 IV
- Radial velocity: −19 km/s
- Proper Motion: 0.097 arcsecs/year
- Apparent Visual Magnitude: 0.45
- Absolute Visual Magnitude: −2.77
- Luminosity: 5250 Solar Luminosities
- HD number: 10144
Fiction
- Achenar is the seat of the Emperor in computer game Elite
External links
- Achernar at solstation.com
- Achernar at absoluteastronomy.com
- http://www.focus.it/notizie/10577_17_6_28.asp?Npag=2 (Italian language)
- Achernar at fractaluniverse.org
