What is Altair?
'''Altair''', also called '''α&nbsp;Aquilae''', '''α&nbsp;Aql''', is the brightest [[star]] in the [[constellation]] of [[Aquila (constellation)|Aquila]]. It is the [[list of brightest stars|twelfth brightest star]] in the night sky. It is in the [[G-cloud]]—a fog of gas and dust known as an [[interstellar cloud]].<ref>{{Cite web|url=http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/neighborhood.html|title=Our Local Galactic Neighborhood|last=|first=|website=|publisher=[[NASA]]|access-date=|archive-date=2013-11-21|archive-url=https://web.archive.org/web/20131121061128/http://interstellar.jpl.nasa.gov/interstellar/probe/introduction/neighborhood.html|url-status=dead}}</ref><ref>{{Cite news|url=http://www.centauri-dreams.org/?p=14203|title=Into the Interstellar Void|last=Gilster|first=Paul|date=2010-09-01|work=Centauri Dreams|access-date=2017-03-26|language=en-US}}</ref> Altair is an [[stellar classification|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]]).<ref name=darlingsummer>[http://www.daviddarling.info/encyclopedia/S/Summer_Triangle.html Summer Triangle], entry, ''The Internet Encyclopedia of Science'', David Darling. Accessed on line November 26, 2008.</ref> It is 16.7 [[light-years]] (5.13 [[parsec]]s) from the [[Sun]] and is one of the [[List of nearest stars|closest stars]] visible to the naked eye.<ref>{{Cite book|title=The brightest stars : discovering the universe through the sky's most brilliant stars|url=https://archive.org/details/brighteststars00scha|last=Hoboken|first=Fred Schaaf|publisher=John Wiley & Sons, Inc.|year=2008|isbn=978-0-471-70410-2|location=New Jersey|pages=[https://archive.org/details/brighteststars00scha/page/194 194]|oclc=440257051}}</ref> Altair spins rapidly, with a velocity at its [[equator]] of about 286&nbsp;km/s.<ref>From values of ''v'' sin ''i'' and ''i'' in the second column of Table 1, Monnier et al. 2007.</ref><ref na