A planet (right) orbits close to Alpha Centauri B, the second-largest star of the triple Alpha Centauri system, in this artist's concept. The most massive star of the system, Alpha Centauri A, is at lower left. (The third star, Proxima Centauri, is out of view.) The bright star at top right is the Sun. Alpha Centauri is the closest star system to our own, at a distance of just 4.3 light-years. [ESO/L. Calçada/Nick Risinger]