Presupernova neutrinos: realistic emissivities from stellar evolution

TL;DR

This paper provides a detailed calculation of neutrino emissions from massive stars in their final stages before supernova, incorporating updated nuclear rates and realistic stellar conditions, highlighting the significance of beta processes.

Contribution

It introduces a comprehensive model of neutrino emissivities during presupernova stages using advanced stellar evolution data and updated nuclear physics.

Findings

Beta decay and electron capture significantly contribute to neutrino emission.

Neutrino spectra are influenced by detailed stellar conditions and nuclear processes.

Results indicate detectable neutrino signals from presupernova stars.

Abstract

We present a new calculation of neutrino emissivities and energy spectra from a massive star going through the advanced stages of nuclear burning (presupernova) in the months before becoming a supernova. The contributions from beta decay and electron capture, pair annihilation, plasmon decay, and the photoneutrino process are modeled in detail, using updated tabulated nuclear rates. We also use realistic conditions of temperature, density, electron fraction and nuclear isotopic composition of the star from the state of the art stellar evolution code MESA. Results are presented for a set of progenitor stars with mass between 15 $M_\odot$ and 30 $M_\odot$. It is found that beta processes contribute substantially to the neutrino emissivity above realistic detection thresholds of few MeV, at selected positions and times in the evolution of the star.