They produce energy in the triple-alpha process, the proton-proton chain, or the (*) CNO cycle.
The first step in the creation of these objects is ambipolar diffusion. They create jets known as Herbig-Haro objects, which are expelled into the H-2 regions where they often form. They produce energy in the triple-alpha process, the proton-proton chain, or the (*) CNO cycle. A plot of the effective temperatures against the luminosities of these objects is the Hertzsprung-Russell diagram, which contains the "main sequence" of their life spans. For 10 points, name these massive objects that undergo fusion, examples of which include Sirius and the Sun.
The first step in the creation of these objects is ambipolar diffusion.
{stars} [accept {protostars} until "triple alpha"; do not accept any other more specific answers]