First light on starbirth

The paper describes the work carried out on protostars and their development into stars. Protostars were recently detected by the Infrared Astronomical Satellite, IRAS. Observations of these protostars led to an understanding of the entire sequence of starbirth, for a star as heavy as the sun. The formation of a protostar and how it grows is outlined, as well as its development into a T Tauri star with a surrounding disc of dust. The disc may last for a million years before its matter either falls onto the star, is blown away by the outflows, or condenses into planets. (U.K.)