^BCentaurus, Crux & Carina constellations.^b Starfield featuring the constellations of Centaurus (left), the Southern Cross (Crux Australis, centre) and Carina (right). At lower centre is the Coal Sack, an interstellar cloud (nebula) of dust which blocks the light of stars behind it. The two bright stars seen in Centaurus are Hadar (Alpha Centauri, blue) & Rigil Kentaurus (Beta Centauri, white). The crucifix-shaped Southern Cross is defined by four bright stars. The most distinctive object in Carina is the large, red region known as Eta Carinae (NGC 3372). This consists of an interstellar cloud (nebula) of gas and dust around a star which varies in brightness.