Neutrino-induced nucleosynthesis and the site of the r-process

Abstract

If the r-process occurs deep within a Type II supernova, probably the most popular of the proposed sites, abundances of r-process elements may be altered by the intense neutrino flux. We point out that the effects would be especially pronounced for 8 isotopes that can be efficiently synthesized by the neutrino reactions following r-process freeze-out. We show that the observed abundances of these isotopes are entirely consistent with neutrino-induced nucleosynthesis, strongly arguing for a supernova r-process site. The deduced fluences place stringent constraints on the freeze-out radius and dynamic timescale of the r-process.