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ALTAIR


'Altair' (α Aql / α Aquilae / Alpha Aquilae / Atair ) is the brightest star in the constellation Aquila and the twelfth brightest star in the nighttime sky, at visual magnitude 0.77.
Altair is a vertex of the Summer Triangle. It is an "A" type or white star located 17 light years away from Earth (about 159 trillion kilometers or 100 trillion miles), one of the closest stars visible to the naked eye.
The name "Altaïr" is Arabic for "the Flying", from the phrase 'نسر الطائر' ''an-nasr aţ-ţā?ir'' "the Flying Eagle".
The spelling "Atair" is also used frequently.
It is officially known as 河鼓二 (Hégǔ'èr, the Second Star of the Drum at the River, or more literally, Riverdrum II) in Chinese. However, it is more famous known as its other names: 牵牛星 or 牛郎星 (the Star of the Cowherd), after the Cowherd in the Chinese mythology: the Cowherd and the Weaver Girl.
Altair is most notable for its extremely rapid rotation; by measuring the width of its spectral lines, it was determined that its equator does a complete rotation in about 6½ hours (various other sources give 9 hours, or 10.4 hours). For comparison, our Sun requires just over 25 days for a complete rotation. As a result of its rapid rotation, Altair is oblate: its equatorial diameter is at least 22 percent greater than its polar diameter. Recently, images of the surface of Altair have been captured. This is the first visual verification of gravity darkening.
Altair, along with Beta Aquilae and Gamma Aquilae, form the well-known line of stars sometimes referred to as the shaft of Aquila.

Contents
Location
Altair in mythology and culture
See also
External links

Location


The star's location in the constellation of Aquila is shown in the following map:

Altair in mythology and culture


In Chinese mythology, there is a love story of Qi Xi in which Niu Lang ('Altair') and his two children (Aquila -β and -γ) are separated forever from their mother Zhi Nü (Vega) who is on the far side of the river, the Milky Way. The Japanese Tanabata festival is also based on this legend.
In astrology, the star Altair was ill-omened, portending danger from reptiles.

See also



Altair in fiction

External links



Report on ultra high-resolution photograph.

SolStation

Secrets of Sun-like star probed

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