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 . 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 .