MAGNETOROTATIONALLY DRIVEN SUPERNOVAE AS THE ORIGIN OF EARLY GALAXY <i>r</i> -PROCESS ELEMENTS?

TLDR

The study investigates whether magnetorotationally driven supernovae can produce r‑process elements in the early Galaxy. The authors performed nucleosynthesis calculations on tracer particle histories from a 3D magnetohydrodynamical core‑collapse supernova model, comparing results with and without neutrino absorption on the electron fraction. Neutrino absorption shifts and broadens the electron‑fraction distribution, yet both scenarios reproduce the solar r‑process peaks, indicating that rapidly rotating, strongly magnetized progenitors can account for early Galactic r‑process enrichment.

Abstract

We examine magnetorotationally driven supernovae as sources of r-process elements in the early Galaxy. On the basis of thermodynamic histories of tracer particles from a three-dimensional magnetohydrodynamical core-collapse supernova model with approximated neutrino transport, we perform nucleosynthesis calculations with and without considering the effects of neutrino absorption reactions on the electron fraction (Ye) during post-processing. We find that the peak distribution of Ye in the ejecta is shifted from ∼0.15 to ∼0.17 and broadened toward higher Ye due to neutrino absorption. Nevertheless, in both cases, the second and third peaks of the solar r-process element distribution can be reproduced well. The rare progenitor configuration that was used here, characterized by a high rotation rate and a large magnetic field necessary for the formation of bipolar jets, could naturally provide a site for the strong r-process in agreement with observations of the early Galactic chemical evolution.