A Long, Cold, Early r-process? Neutrino-induced Nucleosynthesis in He Shells Revisited

TL;DR

This paper explores a neutrino-driven r-process in the helium shells of early supernovae, which could produce heavy element peaks at low metallicity and temperature, impacting our understanding of metal-poor star abundances.

Contribution

It revisits and refines the neutrino-induced r-process mechanism in supernova He shells, highlighting its potential to produce heavy elements at low metallicity and the importance of neutrino physics.

Findings

Potential to produce A ~ 130 and 195 peaks in early stars.

Sensitivity of the process to neutrino emission and oscillations.

Implications for interpreting metal-poor star abundance data.

Abstract

We revisit a neutrino-driven r-process mechanism in the He shell of a core-collapse supernova, finding that it could succeed in early stars of metallicity < solar/1000, at relatively low temperatures and neutron densities, producing A ~ 130 and 195 abundance peaks over ~ 10-20 s. The mechanism is sensitive to the neutrino emission model and to neutrino oscillations. We discuss the implications of an r-process that could alter interpretations of abundance data from metal-poor stars, and point out the need for further calculations that include effects of the supernova shock.