Light hyperclusters and hyperons in low-density hot stellar matter

TL;DR

This paper models the impact of hyperons and light nuclei on low-density hot stellar matter, revealing how hyperons influence cluster dissolution and abundance in supernova-like environments.

Contribution

It introduces a relativistic mean-field model with density-dependent couplings to analyze hyperon and light nucleus abundances in stellar matter, highlighting the effects of hyperons on cluster formation.

Findings

Hyperons delay cluster dissolution to higher densities.

Hyperons increase cluster abundance, especially at higher temperatures.

Hyper-nuclei can surpass alpha particles in abundance at certain conditions.

Abstract

The abundance of light nuclei and hyperons, that are produced in stellar environments such as supernova or binary mergers, is calculated within a relativistic mean-field model with density dependent couplings in low-density matter. Five light nuclei are considered, together with three light hyper-nuclei. We show that the presence of hyperons shifts the dissolution of clusters to larger densities, and increases the amount of clusters. This effect is larger the smaller the charge fraction, and the higher the temperature. The abundance of hyperons is also affected by the cluster formation: neutral and positively charged hyperons suffer a reduction, and the negatively charged ones an increase. We also observe that the dissolution of the less-abundant clusters occurs at larger densities due to smaller Pauli-blocking effects. Overall, hyper-nuclei set in at temperatures above 25 MeV, and depending on the temperature and chemical composition, they may be more abundant than $\alpha$-particles, or even more abundant than other heavier clusters.