The Alpha Centauri system, commonly called Alphacen, consists of three stars.
The primary star of the system star is called Rigil (Formerly Alpha Centauri A). Rigil Kentaurus was an older name for the system). It a class G2 star a little larger than Sol. It has a small family of 5 planets.
Its companion Tolman (formerly called Alpha Centaur B, and given another old name for the entire system), a class K0 star, has a smaller family of 4 planets.
Rigil and Tolman orbit their common center of gravity in an eccentric orbit, and vary from 11 AU at closest approach to 43 AU
Proxima, a distant companion (.07 parsec) to Rigil and Tolman, is a very small M5.5 Ve dwarf, just large enough to be called a star, with a number of dwarf planets attending it. Although observations from Earth had made it uncertain whether the system was in fact gravitationally bound to Alpha Centauri A and B, more accurate measurements of distance and mass from close up confirmed that it was indeed weakly bound to the system, though at such a distance that it still continued to be treated for some purposes as a separate system.
Alphacen is 1.27 parsec from Sol and 2.04 parsec from Barnard. Wolf 359 at 2.5 parsec is at present out of reach.
History
In the third century, the first primitive jump drive was developed and cent to the Alpha Centauri system. The first one-way unmanned probe, sent to Proxima Centauri and broadcast its automated mesage. The first manned expedition also reached its destination but failed to return:, the second never arrived. The third successfully returned, though several of the crew did not survive. The fourth, a significantly larger ship, with detailed observations of the Alphacent system made from Proxima Centauri, was sent to Alpha Centauri, and returned with its scientific mission complate but no survivors. The first colony planted in the Alphacent system was set up to provide purified fuel as well as begin mapping the Alphacent systen. It struggled and numerous members died, but by the end of the century, experienced colonists from Luna, Mars, and Callisto emigrated and stabilized, it. Regular monthly visits and in-system craft helped expand the colony. By the end of the century, it began to show success.
Note: This article is a work of fiction. Resemblances to the real Alpha Centauri system are intentional.