Any star that has evolved past the protostar stage, but has not yet arrived on the main sequence. There is a variety of YSOs depending on their age, mass, and environment, including Herbig stars, T Ta
uri stars, and, in general, compact infrared sources embedded in molecular clouds.
Any star that has evolved past the protostar stage, but has not yet arrived on the main sequence. There is a variety of YSOs depending on their age, mass, and environment, including Herbig stars, T Ta
uri stars, and, in general, compact infrared sources embedded in molecular clouds.