Altair

Altair, also called α Aquilae, α Aql, is the brightest star in the constellation of Aquila.

It is the twelfth brightest star in the night sky. It is in the G-cloud—a fog of gas and dust known as an interstellar cloud. Altair is an A-type main sequence star with an apparent visual magnitude of 0.77. It is one of the vertices of the  Summer Triangle (the other two vertices are Deneb and Vega).Summer Triangle, entry, The Internet Encyclopedia of Science, David Darling.  Accessed on line November 26, 2008. It is 16.7 light-years (5.13 parsecs) from the Sun and is one of the closest stars visible to the naked eye.

Altair spins rapidly, with a velocity at its equator of about 286 km/s.From values of v sin i and i in the second column of Table 1, Monnier et al. 2007. This is a significant fraction of the star's estimated breakup speed of 400 km/s.Robrade J. & Schmitt J.H.M.M. 2009. Altair - the "hottest" magnetically active star in X-rays. Astronomy and Astrophysics, 497 (2): 511–520 A study with the Palomar Testbed Interferometer showed that Altair is not spherical, but is flattened at the poles due to its high rate of rotation. Other interferometric studies with multiple telescopes, operating in the infrared, have confirmed this. 

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Category:Stars