Original: A third star, known as Proxima Centauri, Proxima or Alpha Centauri C (Î Cen C), is likely gravitationally associated with the closer binary, Alpha Centauri AB.
Simplified: Alpha Centauri is a triple star system. It consists of two main stars, Alpha Centauri A and Alpha Centauri B (which form a binary star together) at a distance of 4.36 ly, and a dimmer red dwarf named Proxima Centauri at a distance of 4.22 ly.