Vega, << VEE guh, >> also known as Alpha Lyrae, ranks as the sixth brightest star in the sky. As seen from Earth, only the sun and four other stars shine more brightly. Vega is the brightest star in the constellation Lyra, the Harp. The star appears in Earth’s northern sky.
Vega is a main-sequence star. Main-sequence stars produce most of their energy by fusing (combining) hydrogen nuclei in their cores. Vega’s mass (amount of matter) measures about 2.3 times that of the sun. It produces roughly 35 times as much power as does the sun.
Astronomers group Vega in the A spectral class (see Star (Spectral classes)). Stars in this class typically appear white or bluish-white. Vega and two other bright A stars, Altair and Deneb, form the Summer Triangle. It appears on summer evenings in the Northern Hemisphere.
In 2006, astronomers announced that Vega is rotating at speeds nearly high enough to cause it to break apart. The rotation causes Vega to swell at its equator, where its diameter is about 25 percent greater than the distance between its poles. The rotation also causes Vega’s temperature to rise toward its poles, which are about 30 percent hotter than its equator.
See also Lyra; North Star; Star (table: The 10 brightest stars as seen from Earth).
