Alpha Aquilae


Distance (Light Years) 16.77 ± 0.08
Apparent Magnitude 0.76
Color (B-V)0.22

Names For This Star

The name Altair is derived from the Arabic name for the constellation of Aquila: Al Nasr al Tair. An alternative spelling for the star name is "Atair."

Description of the Star

Altair is a white A7V main sequence star. The star is about 1.6 times the diameter of the sun.

The spectral type implies an effective temperature of 8100 K, a luminosity about 9 times that of the sun, and a mass almost twice that of the sun.

According to Burnham Altair is one of the most rapidly rotating stars known. The rotational speed at the equator, as determined from the spectrum, amounts to 160 km/s, which implies a rotational period of about 6.5 hours. (The equatorial rotation period of the sun is 25.4 days.) This very rapid rotation suggests that the star is very appreciably flattened by centrifugal force, so that the polar diameter might be one half of the diameter measured across the equator.

Other Designations For This Star


53 Aquilae

Hipparcos Identifier (HIP Number)


Harvard Revised (HR Number)


Henry Draper Catalog (HD Number)


Bonner Durchmusterung (BD Number)

BD+08 4236
Smithsonian Astrophysical
Observatory compendium (SAO Number)

Fundamental Katalog (FK5 Number)



Copyright © 1998 - 2010 by Arnold V. Lesikar,
Professor Emeritus
Dept. of Physics, Astronomy, and Engineering Science,
St. Cloud State University,St. Cloud, MN 56301-4498

Feedback to: editor AT