If fusion rate decreases, what corrective mechanism restores hydrostatic balance?

Gravity compresses the core, increasing temperature and speeding up fusion.

The stellar interior maintains stability through a profound self-regulating feedback loop designed to preserve hydrostatic equilibrium. If the nuclear fusion rate in the core were to momentarily decrease, the outward thermal pressure would drop slightly, allowing gravity to gain a temporary advantage. This increased gravitational dominance causes the core material to compress. This compression, in turn, dramatically increases the core's temperature and density. This hotter, denser environment naturally accelerates the rate of nuclear fusion until the increased outward energy production precisely counteracts the gravitational pull once again, restoring the perfect balance.