Speculations on the fizzled collapse of a massive star

The physics of the long-term accretion phase of a stellar collapse that does not lead to a supernova is addressed. A trapped surface should form early on in this accretion phase. It is shown, using a simple analysis of the radius dependence of the physical profiles, that, even when nuclear burning and supersonic turbulence are included, the envelope, where most of the progenitor's mass resides, can never achieve temperatures sufficient to radiate more than a negligible fraction of its rest mass in neutrinos before it is swallowed by the black hole. The neutrino emissions during the pre-black hole, Kelvin-Helmholtz phase of the inner core should dominate the total integrated neutrino flux even when the supernova fizzles. This flux should be comparable to, and only slightly larger than, the integrated flux during neutron star formation.