Hubble Spotlights a Supernova – NASA Science

Several evolutionary paths can lead to a supernova explosion. One is the death of a supermassive star. When a supermassive star runs out of its hydrogen fuel, it begins a stage where it fuses the remaining elements to heavier and heavier ones. These final fusion reactions generate less and less outward force (radiation pressure) to balance the star’s gravitational tug inward. As heavier elements form in the star’s core, the core itself begins to fully collapse under its own gravity, and the star’s outer layers blast away in a supernova explosion. Depending on the star’s original mass, its core may collapse to nothing but neutrons, leaving behind a neutron star, or its gravity may be so great that it collapses to a black hole.