What is Pre-main-sequence star?
A '''pre-main-sequence [[star]]''' known as a '''PMS star''' or PMS object, is a star when it has not reached the [[main sequence]] stage yet. Before, the object is a [[protostar]]. It grows by getting [[mass]] from the surrounding interstellar dust and [[gas]]. [[File:Pre-main_sequence.jpg]] After the protostar blows off the envelope, it will be visible. It then appears on the [[stellar birthline]] in the [[Hertzsprung–Russell diagram|Hertzsprung-Russell diagram]]. At this point, the star has got nearly all of its mass. It has not started the [[nuclear fusion]] of hydrogen. The star then contracts. Its internal temperature rises until it begins burning hydrogen. The star is then in the pre-main sequence stage.<ref>{{Cite web|title=Institute for Astronomy|url=http://www.ifa.hawaii.edu/|access-date=2022-05-22|website=www.ifa.hawaii.edu}}</ref> == References == {{reflist}} [[Category:Types of stars]]