Alpha Centauri is a triple star system located only 4.3 light years away towards the constellation Centaurus. It is the closest star system to our own, with Proxima Centauri, the dimmest of the three, as the closest star. Alpha Centauri A and B form a binary system, orbiting each other at a distance only slightly more than that between Uranus and our Sun.
Alpha Centauri A, also called Rigil Kentaurus, is the brightest star in the constellation Centaurus and is the same type of star as our Sun. Alpha Centauri B is smaller and less bright than our Sun, but is still similar. The first Earth sized exoplanet orbiting a Sun like star was discovered orbiting Alpha Centauri B, though its orbit is much too small and thus the planet is much too hot for life as we know it to exist there.