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?

  • $\begingroup$ Good question. I posted relevant half-life info & a couple of links here. $\endgroup$ – PM 2Ring Feb 15 at 17:49
  • $\begingroup$ The half life of Ni-56 is 6.1 days, the half life of Co-56 is 77 days. $\endgroup$ – Jon Custer Feb 15 at 17:56
  • $\begingroup$ @JonCuster, so the answer you're giving is that only a very small fraction of the core is iron? (Given that silicon burning occurs for only a few days.) $\endgroup$ – NeutronStar Feb 15 at 19:02
  • $\begingroup$ @Joshua - I think that one needs to follow all the options for what the isotope yields of silicon burning and then what happens, because there is plenty going on in the core. But, if you only consider the Si-28 + Si-28 -> Ni-56 reaction, the only half-lives to really consider are how Ni-56 decays down to Fe-56. But, there is more going on. $\endgroup$ – Jon Custer Feb 15 at 19:13

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