The position of Achernar

Achernar (α Eri / α Eridani / Alpha Eridani) is the brightest star in the constellation Eridanus and the ninth brightest star in the nighttime sky. Image File history File links The position of Alpha Eridani (Achernar) By Zwergelstern Thanks for the help of Patrick Chevalley File links The following pages link to this file: Achernar ... Image File history File links The position of Alpha Eridani (Achernar) By Zwergelstern Thanks for the help of Patrick Chevalley File links The following pages link to this file: Achernar ... Alpha (uppercase Α, lowercase α) is the first letter of the Greek alphabet. ... Orion is a remarkable constellation, visible from most places on the globe (but not always the whole year long). ... Eridanus is the sixth largest of the 88 modern constellations. ... Bright stars can be bright because they produce more light, because they are closer to us, or both. ...

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 September when most other bright southern stars are skirting the horizon. A supergiant is a very large type of star which is ~10 to 50 solar masses on the Hertzsprung-Russell diagram. ... The Pleiades star cluster A star is any massive gaseous body in outer space. ... Earth, also known as the Earth, Terra, and (mostly in the 19th century) Tellus, is the third-closest planet to the Sun. ... The Southern Hemisphere is the half of a planets surface (or celestial sphere) that is south of the equator (the word hemisphere literally means half ball). On Earth it contains four continents (part of Africa, Australia, most of South America, and Antarctica) and four oceans (South Atlantic, Indian, Pacific...

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. For other uses, see sphere (disambiguation). ...

It is approximately 144 light years from the Solar System. A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... Presentation of the solar system (not to scale) The solar system consists of the Sun, all the objects that orbit around it, including meteoroids, planetoids, comets, moons, and planets, and the tenuous plasma of the interplanetary medium. ...

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

The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... This article is about the star. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequenly refined in terms of other characteristics. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... The apparent magnitude (m) of a star, planet or other heavenly body is a measure of its apparent brightness; that is, the amount of light received from the object. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standardized distance away. ... // In General Physics In general physics, luminosity (more properly called luminance) is the density of luminous intensity in a given direction. ... The Henry Draper Catalogue is an astronomy catalogue with astrometric and spectroscopic data about more than 225,000 stars. ...

Fiction

• Achenar is the seat of the Emperor in computer game Elite

Elite is a seminal space trading-game, originally published by Acornsoft in 1984 for the BBC Micro and Acorn Electron computers and subsequently ported to many others. ...

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