Alpha and Proxima Centauri

The sky around the bright star Alpha Centauri and the much fainter red dwarf star, Proxima Centauri (faint red star, lower-right), the closest star to the Solar System. Proxima is just 4 light-years from the Solar System, in the constellation Centaurus. In 2016 astronomers found clear evidence of a planet orbiting Proxima Centauri. The world, designated Proxima b, orbits its parent star every 11 days and has a temperature suitable for liquid water to exist on its surface. This rocky world is a little more massive than Earth and is the closest exoplanet to us. It orbits about 7 million kilometres from Proxima Centauri. Although Proxima b orbits much closer to its star than Mercury does to the Sun, the star itself is far fainter than the Sun. As a result Proxima b lies well within the habitable zone. This image was created from photographic material taken with the 1.22-metre UK Schmidt Telescope at Anglo-Australian Observatory, forming part of the Digitized Sky Survey 2. Photo by DAVIDE DE MARTIN/SCIENCE PHOTO LIBRARY