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, one of the closest stars visible to the naked eye.

The name "Altair" is Arabic for "the flyer", from the phrase نسر الطائر an-nasr aţ-ţā?ir "the flying eagle". The spelling "Atair" is also used frequently.

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 6 1/2 hours (various other sources give 9 hours, or 10.4 hours). In comparison, our star, the Sun, requires a little more than 25 days for a complete rotation. As a result of its rapid rotation, Altair is oblate: its equatorial diameter is at least 14 percent greater than its polar diameter.

Altair, along with Beta Aquilae and Gamma Aquilae , form the well-known line of stars sometimes referred to as the shaft of Aquila.

Coordinates (Equinox 2000):

• R.A.: 19h50m47.00s
• Dec.: +08°52'06.0"

References to the star

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.

In astrology, the star Altair was ill-omened, portending danger from reptiles.

In computing, an important early microcomputer, the Altair 8800, was named after the star because the daughter of the man responsible for coming up with a suitable name, when asked what she thought the computer should be called, was watching an episode of Star Trek where the Starship Enterprise had the Altair as its destination. So Altair it was.

In science fiction, Altair is:

• The planet Altair IV is the main setting of the book and film Forbidden Planet
• The homeworld of Harlan, an artificial lifeform in Stargate SG-1

External link

• Report on ultra high-resolution photograph.