Which characteristic activity distinguishes the turbulent protostar stage from a stable main-sequence star?

Answer

Shedding mass and angular momentum through bipolar outflows

Protostars are highly active, shedding mass and clearing surrounding material via powerful, collimated jets emanating from the poles, processes that largely cease once the star achieves stable fusion and hydrostatic balance.

Which characteristic activity distinguishes the turbulent protostar stage from a stable main-sequence star?
protostarstellar evolutionstar formationastrophysicscollapse