If the final element to be fused in a star is iron, where does everything after that come from?

Question

If the final element to be fused in a star is iron, where does everything after that come from?

In: 154

Answer 1

So, the idea here is that iron (specifically iron-56) has the lowest energy of any atomic nucleus. In other words, trying to fuse iron will be endothermic (absorbing energy) rather than exothermic (releasing energy) as is the case for lighter elements. So, by the time a star reaches iron, its core is no longer able to produce energy and so it collapses.

It’s long been thought that supernovas produced elements heavier than iron. So, while producing these heavier elements does absorb energy, the supernova provides enough energy to do this. More recent discoveries have suggested that collisions between neutron stars, The remnants of stellar cores following a supernova, are responsible for many of the heavier elements in the universe. These collisions take place in binary system consisting of two neutron stars orbiting each other other. They slowly spiraling towards each other and eventually meet.