What specific term describes the purely mechanical heating process driving a protostar's luminosity?

Answer

Kelvin-Helmholtz contraction

The mechanism where intense compression caused by gravity heats the protostar, dictating its position on the H-R diagram before fusion, is referred to by astronomers as Kelvin-Helmholtz contraction.

What specific term describes the purely mechanical heating process driving a protostar's luminosity?
protostarstellar evolutionstar formationastrophysics