Explaining the Sr and Ba Scatter in Extremely Metal-Poor Stars

TL;DR

This paper investigates the observed variations in Sr and Ba abundances in extremely metal-poor stars, proposing a supernova-based model and turbulence effects to explain the data's cutoff and scatter.

Contribution

It introduces a model linking supernova explosions and turbulence to the Sr/Ba abundance patterns in metal-poor stars, explaining observed features.

Findings

Supernova collapse models reproduce key abundance features.

Turbulence significantly contributes to abundance scatter.

Model aligns with galactic chemical evolution constraints.

Abstract

Compilations of abundances of Strontium and Barium in extremely metal-poor stars show that an apparent cutoff is observed for [Sr/Ba] at [Fe/H]$<$-3.6 and large fluctuations for [Fe/H]$>$-3.6 with a clear upper bound depending on metallicity. We study the factors that place upper limits on the logarithmic ratio [Sr/Ba]. A model is developed in which the collapses of type II supernovae are found to reproduce many of the features seen in the data. This model is consistent with galactic chemical evolution constraints of light-element enrichment in metal-poor stars. Effects of turbulence in an explosive site have also been simulated, and are found to be important in explaining the large scatter observed in the [Sr/Ba] data.