A protostar (or protostar ) is a cluster of Gaz and a little dust contracting to form a star. The Matière concentrates on itself and whirls around a center of Gravité, future heart of the star. The fall of the Matière towards its center makes protostar increasingly luminous until the dust which it attracted prevents the visible light from passing. The protostar surrounded by a cocoon of dust becomes a obscure Globule then. The protostar becomes a star when they are not any more the shocks of the Matière but of the nuclear reactions which illuminates it.

See too

• Birth of the stars
• Evolution of the stars