Vega - α Lyrae

Vega (α Lyr, α Lyrae, Alpha Lyrae) is the brightest star in the constellation (opens in a new tab) Lyra (opens in a new tab), the fifth brightest star (opens in a new tab) in the night sky and the second brightest star in the northern celestial hemisphere (opens in a new tab), after Arcturus (opens in a new tab). It is a relatively close star at only 25 light-years (opens in a new tab) from Earth, and, together with Arcturus and Sirius (opens in a new tab), one of the most luminous stars in the Sun (opens in a new tab)'s neighborhood. Vega has been extensively studied by astronomers, leading it to be termed “arguably the next most important star in the sky after the Sun.”Vega was the northern (opens in a new tab) pole star (opens in a new tab) around 12,000 BC and will be so again around AD 13,727.

Vega is only about a tenth of the age of the Sun, but since it is 2.1 times as massive its expected lifetime is also one tenth of that of the Sun; both stars are at present approaching the midpoint of their life expectancies. Vega has an unusually low abundance of the elements with a higher atomic number (opens in a new tab) than that of helium (opens in a new tab).Vega is also a suspected variable star (opens in a new tab) that may vary slightly in magnitude in a periodic manner. It is rotating (opens in a new tab) rapidly with a velocity of 274 km/s at the equator. This is causing the equator to bulge outward because of centrifugal (opens in a new tab) effects, and, as a result, there is a variation of temperature across the star’s photosphere (opens in a new tab) that reaches a maximum at the poles. From Earth, Vega is being observed from the direction of one of these poles.

Based on an observed excess emission of infrared (opens in a new tab) radiation, Vega appears to have a circumstellar disk of dust. This dust is likely to be the result of collisions between objects in an orbiting debris disk (opens in a new tab), which is analogous to the Kuiper belt (opens in a new tab) in the Solar System (opens in a new tab). Stars that display an infrared excess because of dust emission are termed Vega-like stars. Irregularities in Vega’s disk also suggest the presence of at least one planet, likely to be about the size of Jupiter (opens in a new tab),in orbit around Vega.