3

For stars that undergo core collapse (leading to a core-collapse supernova or direct blackhole formation), the final stage of nuclear burning is silicon burning. Most online references I've found state that an iron core is the final stage of silicon burning, but a few references and stuff I vaguely remember from my classes state that the final core is an iron-nickel core, with Ni-56 being the actual final product of silicon burning and then decaying to Fe-56.

In the final core that undergoes core collapse and creates the explosion we call a supernova, what fraction of the core is iron vs. nickel?

NeutronStar
  • 5,473

1 Answers1

0

Given the high temperatures, Ni decays to Fe 56 within minutes. So, you will find mostly iron. In case of a star the size of Betelgeuse, supernova occurs at roughly 4 to 5 hours after silicon is exhausted in the core. By that time, shell silicon burning has already moved too far. But don't expect there to be only iron. As temperature increases, even iron is no longer stable. You will find a mixture of elements close to iron. Neutronization occur (electrons merge with protons, creating neutron rich isotopes). Neutronozation occurs mostly in the inner part of the core. The shell, which burned silicon for 4 hours, is now mostly made of Fe 56. So, the inner part of the core is made of exotic, neutron rich elements, the outer part is a mixture dominated by Fe 56, while the shell is almost entirely made of Fe 56.

Anaimfinity
  • 1