The Alpha Centauri star system contains three stars: Alpha Centauri A, Alpha Centauri B and Proxima Centauri (or Alpha Centauri C). Collectively they are known as ‘Alpha Centauri AB-C’.
Alpha Centauri A and B are a binary pair, orbiting each other with a maximum distance 35.6 AU and a minimum distance of 11.2 AU. Collectively they are known as Alpha Centauri AB and from the Earth they are indistinguishable from each other with the naked eye.
Alpha Centauri A is a main sequence yellow star and is slightly larger than our own sun, while Alpha Centauri B is slightly smaller than our sun and is orange-yellow in colour.
Proxima Centauri (Alpha Centauri C) is a much smaller red dwarf star. It orbits the binary pair Alpha Centauri AB at a distance of 0.2 light years (13,000 AU), each orbit taking between 100,000 and 500,000 years.
Alpha Centauri is the brightest star in the southern constellation of Centaurus (seen from Earth) and a binary star system, Alpha Centauri AB (α Centauri AB). To the unaided eye it appears as a single star, whose total visual magnitude would identify it as the third brightest star in earth’s night sky.
α Centauri A (Rigel Kentaurus) is a class G star (G2V) – a yellow star similar to Earth’s own Sun. In 2350 a Chinese exploratory expedition entered the the system, discovering an inhabitable planet in the 5th orbit. Named Tiengong after the ancient Chinese diety ‘The Jade Emperor’ it was first colonized in 2375, becoming the first extra-solar community in human history.
α Centauri B (Toliman) is a class K star (K6V) – an orange star slightly smaller than Earth’s sun.