Altair (Alpha Aquilae)
The brightest star in the constellation Aquila, the
twelfth brightest star in the sky, and the southern point of the Summer
Triangle. Its Arabic name comes from a phrase meaning "the flying eagle."
|Altair. Image credit: NASA/JPL
|© 2005 Torsten Bronger
Altair is a white A star that, at a distance of
under 17 light-years, is one of the nearer solar neighbors. It is moving
relatively fast against the background of distant stars and will shift by
as much as a degree over the next 5,000 years. It is also a rapid rotator
with an equatorial spin speed of 242 km/s, compared with the Sun's 2 km/s.
As a result, despite having a radius greater than that of the Sun, Altair
manages to complete a rotation every nine hours. Its estimated age is less
than one billion years.
||16.72 light-years (5.13 pc)
|position (epoch J2000)
||R.A. 19h 50m 47.0s,
Dec. +08° 52' 06"
||53 Aquila, HD 187642,
HR 7557, BD+08°4236,
GCTP 4665.00, GJ 768,
LHS 3490, HIP 97649
Altair surface features
In 2007, Altair became the first star, other than a giant or supergiant
star (such as Betelgeuse), to have its
surface features imaged. This feat was achieved by combining
the light of four telescopes at Georgia State University's Center for High
Resolution Angular Astronomy (CHARA). The results confirmed that Altair
is spinning so rapidly on its axis that it is stretched out into an elongated
shape. The image of Altair obtained by CHARA also revealed that the amount
of distortion and changes in surface temperature at the equator differed
from those predicted current theoretical models.
|The first image of Altair's surface
in science fiction
Among many science fiction references to Altair, the planet Altair IV is
the scene of the book and film Forbidden
Planet. The planets Altair III, IV, and V are mentioned in various
episodes of Star Trek. Although no planets
have actually yet been detected by astronomers around Altair, extrasolar
planet detection remains in its infancy and it remains entirely possible
that future studies will reveal that Altair does indeed have a system of
worlds. However, the star's relative youthfulness suggests that any life
on such worlds would be quite primitive.
• brightest stars