Here's a breakdown:

* Protostar: This is the early stage of a star's formation. It's a dense clump of gas and dust that is still collapsing under its own gravity.

* Newborn Star: This term is used more broadly for a star that has just finished forming and is starting to shine on its own.

It's important to note that the term "new star" can also refer to a nova or supernova, which are events where a star experiences a sudden increase in brightness, but this is not the formation of a new star.