What dictates the vastly different endpoints (like white dwarfs or black holes) a star reaches after exhausting its fuel?

Answer

Its initial mass

Once a star exhausts the hydrogen in its core, its subsequent evolutionary path and final fate—leading to endpoints like white dwarfs, neutron stars, or black holes—is sealed by its initial mass.

What dictates the vastly different endpoints (like white dwarfs or black holes) a star reaches after exhausting its fuel?
lifespanstarmasshigh masslow-mass