...we have a tendency to look at this "taxonomically". It used to be phrased "settling unto the main sesequence" to be more descriptive of the stars process. So this mass is collapsing usually out of a larger cloud of stuff. at the point this protostar is massive enough to be what we call a brown dwarf, its already giving off some light and heat , but not enough to fuse hydrogen to helium and not enough "push away" more gas still collapsing in.
Then Boom it gets enough mass to fuse but IIRC its far from stable, often partially blows itself up and subsequently recollapses to ignite its fusion core again, and again until it does stabilize. I believe this stage of settling on is what Cephied Variable stars are.
Ok, thats it. Can you tell I enjoyed your question?
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