Altair By: Nora Lynn Puryear
History and Facts • “The name Altair is derived from the Arabic for “’The Flying Eagle’”. • The star is located about 16.7 light years away from our sun. • It is the 12th brightest star visible from Earth. • Altair is best seen in the summer and autumn skies. • Altair is the brightest star in Aquila.
Constellations • Altair is located in the constellation ‘Aquila’ or ‘the Eagle’. • This constellation lies in the equatorial region. • “It is one of the 48 constellations documented by Greek astronomer Ptolemy in the 2nd century”. • It has a star on each side of it which names are Tarazed and Alshain.
Interesting Facts • Altair is the southern apex of the Summer Triangle. • It rotates at the fast speed of more than 200 km (120 miles) per second. • “Altair is famous for its extremely rapid rotation, which makes its equator perform a complete rotation in about 6 hours, when our Sun requires just over 25 days for a complete rotation. • Pictures taken of its surface show that the fast rotation also causes the equator to be darker, which means the star is cooler there than at the poles.
Magnitude, Color, and Size • Although Altair appears to be blue in many of its pictures, it is a white sub giant which means it’s very hot. • Its apparent magnitude is 0.76 and its absolute is 2.20 which makes this star pretty bright. • “Because of its fast rotation, it has a flattened shape, with its equatorial diameter about 20 percent larger than its polar diameter”. • Higher temperature usually reveals greater mass, at least for Main Sequence stars, and Altair is thought to be in excess of 1.7 times the mass of our sun.
Interesting Facts (Continued) • An eagle is the symbol of the constellation Altair is located in (Aquila). • “On the first of June, Altair rises about 90 minutes after the sunset, as viewed from mid-north latitude.” • “By the end of September it approaches the meridian as night falls.” • “By the end of the year, late-night observers will miss it altogether as it sets less than three hours after the sun.
More Stuff to Know! • “In mythology, Aquila was owned by the Roman god Jupiter and performed many tasks for him.” • “In classical mythology Aquila, and by extension Altair as well, was an eagle favored by Zeus.” • “In another myth Aquila is the eagle that torments Prometheus, and is shot with a poisoned arrow by Hercules.”
Facts, Facts, and More Facts! • “In India, Altair with its two flanking stars, (Tarazed and Alshain), are sometimes thought to be the celestial footprints of the god Vishnu.” • Once visualized, Aquila the Eagle can be seen flying eastward through the Milky Way. • “Altair is separated from the similar-looking (but brighter) star Vega in the constellation Lyra by the great starlit band of the Milky Way.”
Altair • Another fact that makes Altair stand out is that it is a weak and unusual variable star with as many as 9 different rates of brightness waxings and wanings. • “Along with Beta Aquilae and Gamma Aquilae, it forms the well known line of stars sometimes referred to as the Family of Aquila or Shaft of Aquila.” • Also one of the most visible stars to the naked eye.
Star Stuff • “If Altair was substituted for our sun, at the distance the sun is now, life on Earth would be doomed, as Altair shines with 11 times the sun’s visible light.” • Altair has a surface temperature of about 7550 K degrees, which isn’t much hotter than the sun. • Altair is thought to be in excess of 1.7 times the mass of our sun because of its greater mass.
Citations • http://solstation.com/stars/altair.htm • http:/earthsky.org/brightest-stars/altair-the-bluish-jewel-of-the-eagle/ • http://www.topastronomer.com/StarCharts/Constellations/Aquila.php • http://www.britannica.com/EBchecked/topic/17491/Altair • http://www.brighthub.com/science/space/articles/26544.aspx • http://www.freebase.com/view/en/altair