I use this nick ever since that old times in IRC (some 7/8 years ago).
Achernar - Meaning "End of the River":
ACHERNAR (Alpha Eridani). There are 21 classical "first magnitude" stars in the sky. Of these, 10 are so bright that in modern times they had to be placed into even brighter categories, seven into "zeroth" magnitude (the brightest of which is
Alpha Centauri) and two,
Canopus and
Sirius, into the exclusive "minus-first magnitude" group. Of these 10, Achernar ranks number nine, right behind
Procyon in
Canis Minor and just beating out
Betelgeuse in
Orion. Achernar, however, is nowhere nearly as well known to northerners, as
it is a deep southern star, visible only to those who live below 32 degrees north latitude, and easily noted only from the tropics and south. The name, from an Arabic phrase, means "the end of the river," as appropriate for the star that ends the southerly flow of
Eridanus, the River, the celestial depiction of River Ocean, a meandering flow of mostly faint stars that originates with
Cursa, on which Orion rests his foot. Appropriate to its brilliance, Achernar is also the Alpha star, while Cursa, number two, is the Beta. Achernar is so far south that it was not originally part of this long, thin constellation, which originally ended at
Acamar (Theta Eridani), from which Achernar took its name when the river was allowed in more modern times to flow farther to the south. Achernar, a hot class B star, is the hottest of the top ten, rather handily beating out Rigel in Orion. Yet surprisingly, for such a bright star, its temperature is not well known, various measures running from 14,500 to 19,300 Kelvin. From its distance of 144 light years, the lower temperature gives a luminosity 2900 times that of the
Sun, while the upper gives 5400 (the difference caused in part by different estimates of the amount of ultraviolet radiation). The radius then ranges between 8.5 to 6.6 times solar. Interferometer measures show the star to be distinctively flattened, the result of a minimum 225 kilometer-per- second rotation speed. The minor and major axes are respectively measured to be 7.6 by 11.8 Suns across, for an average of 9.9 Suns, which agrees better with that derived from the lower temperature. The higher temperature, however, is more in tune with that indicated by the spectral class. The temperature problem probably has to do with the Achernar's high spin velocity, which helps turn it into a "Be," or "B-emission" star that has a belt of emitting gas circulating in its equator, Achernar losing mass at a rate thousands of times that of the Sun. As a result, the diameter and temperature are both hard to determine. Achernar is also a member of a peculiar class of "Lambda Eridani" stars that show tiny but very regular periodic light variations that may be caused by actual complex pulsations or by rotation and dark "starspots." No one really knows. We do know, however, that Achernar is massive, containing six to eight times the solar mass. It is now normally fusing hydrogen into helium in its deep core and will eventually die as a massive white dwarf like
Sirius- B.
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