For a standard core collapse supernova, the vast majority of the released energy is in the form of neutrinos.

That always astounded me: Neutrinos hardly interact at all, but as I understand supernovas it is the neutrinos that cause all the outer layers of the star to blow off at high speed. Supposedly some of the elements heavier than iron get formed by fusion during that explosion. That's a lot of energy transferred to a lot of mass just from neutrinos. So, that's a LOT of neutrinos.

The actual source of the neutrinos is what, something about making a neutron star out of the iron core of the star? Would that be too many neutrinos for just the iron core?

They are primarily coming from neutron capture (electron + proton -> electron neutrino + neutron). During much of the collapse even these weakly-interacting neutrinos get trapped behind the high-density shock wave. As it expands and the density becomes lower, they escape in what's known as the neutronization burst.

Thanks. Makes sense: The big push, e.g., the shock wave, is not all just directly from just the neutrinos from just the collapsing iron core. Thanks.

I'm no expert, but as far as I'm aware it's a combination of beta decay and thermal neutrino pair production.

Thanks!