Wikipedia:Today's featured article/August 16, 2010

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Photograph of Vega by NASA's Spitzer Space Telescope

Vega is the brightest star in the constellation Lyra, the fifth-brightest star in the night sky and the second brightest star in the northern celestial hemisphere. It is a relatively close star at only 25 light-years from Earth, and one of the most luminous stars in the Sun's neighbourhood. Vega has been extensively studied by astronomers. It was the first star other than the Sun to have its photograph taken and the first to have its spectrum photographed. Historically, Vega served as the northern pole star around 12,000 BCE and will do so again at 13,727 CE. Vega is only about a tenth the age of the Sun, but it is evolving so quickly that it has already approached the midpoint of its life expectancy. It has an unusually low abundance of the elements with a higher atomic number than that of helium. It is rotating rapidly with a velocity of 274 km/s at the equator. Based on an observed excess emission of infrared radiation, Vega appears to have a circumstellar disk of dust. This dust is likely the result of collisions between objects in an orbiting debris disk, which is analogous to the Kuiper belt in the Solar System. Irregularities in Vega's disk also suggest the presence of at least one planet, likely to be about the size of Jupiter. (more...)

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