Achernar is a fixed star at the southernmost end of the constellation of Eridanus and with an apparent brightness of 0.5mag it is its brightest star. So it belongs to the ten brightest stars in the night sky.
Facts about Achernar
The distance from Achernar to earth is 144 light years. It has 6-8 solar masses and belongs as main sequence star to the spectral class B6. The luminosity of Achernar exceeds that of the sun by three thousand times. Its surface temperature is 20,000 K. In addition, Achenar is a binary star, in which its companion star consists of a dwarf star of spectral class A. In 2003, the star Achernar was observed by the astronomical observatory VLTI (Very Large Telescope Interferometer) which revealed that it is very strongly oblate due to its fast rotational speed of at least 230 km/s. Thus the star resembles rather an elliptical body than a ball and ranks therefore among the most strongly flattened fixed stars at all. Since Achernar is located so far south in the night sky, it is not visible from Europe. Only south of the 32nd degree of northern latitude it can be observed.