A protostar is an early stage in the formation of a star, where it contracts mass of gases from its parent molecular cloud. It mainly consists of hydrogen gas.
The protostar was founded by Chushiro Hayashi, a Japanese astrophysicist. who was born and died in Kyoto, Kyoto Prefecture, Japan. The models of the protostar were highly overestimated. Calculations show that a protostar with the same mass as a main-sequence star is larger than the main-sequence star.
The molecular clouds have molecules derived from a small quantity of previous stars. This protostar lasts for an extremely long time, at 10 million years for a star that is caused by supernovas. This would cause separation, and each of those fragments would collpase under gravity, and eventually form a protostar.