Second collapse of a protostar
= Second collapse of a protostar
During continued compression of a <first hydrostatic core>, <molecular hydrogen> dissociation absorbs <energy> and softens the effective <equation of state>. This can trigger a second rapid contraction before a compact stellar core becomes pressure-supported. It is distinct from the initial nearly isothermal collapse and from later <Kelvin-Helmholtz contraction> at roughly fixed <mass>.