Iron will not happily fuse further because this NEEDS energy and where would that energy come from?
"heavier than iron" elements are produced when a star explodes because that collapse produces enormous amounts of energy.
During the collapse, the outer edge of the star is accelerated to something like 20% of the speed of light, that is an ENORMOUS amount of energy slamming down on the core.
Lastly, neutron starts don't produce energy, they are the incompressible remnants of a dead star.
You answer your own question: the energy for further fusion, all the way to neutron degeneracy, is provided by gravitational collapse. The outer layers fusing provide energy for the explosion.
Iron will not happily fuse further because this NEEDS energy and where would that energy come from?
"heavier than iron" elements are produced when a star explodes because that collapse produces enormous amounts of energy.
During the collapse, the outer edge of the star is accelerated to something like 20% of the speed of light, that is an ENORMOUS amount of energy slamming down on the core.
Lastly, neutron starts don't produce energy, they are the incompressible remnants of a dead star.