Properties of Massive Rotating Protoneutron Stars with Hyperons: Structure and Universality

TL;DR

This paper investigates the structure and properties of massive, rotating protoneutron stars with hyperons, analyzing their evolution, the impact of hyperon interactions, and universal relations in hot, young neutron stars.

Contribution

It introduces a detailed study of hyperon effects and universal relations in rotating protoneutron stars using a density-dependent RMF model across evolutionary stages.

Findings

Hyperons significantly affect the star's structure during evolution.

The inclusion of $phi$ meson alters hyperon interactions and star properties.

Universal relations between moment of inertia and compactness hold in hot, young stars.

Abstract

In this work, we study the properties and structure of a massive and rapidly rotating protoneutron star (PNS) with hyperon content. We follow several stages of quasi-stationary evolution in an approximate way at four discrete steps. We use a density-dependent (DD) relativistic mean field theory (RMF) model and calculate different quantities such as mass, equatorial radius, moment of inertia, and quadrupole moment to get different rotating configurations upto the mass-shedding limit. We study the effect of the appearance of $\Lambda$, the lightest of all hyperons, on each of the evolutionary stages of the PNS. We also check its sensitivity to the inclusion of $\phi$ vector meson as a mediator of $\Lambda-\Lambda$ interaction in detail. Finally, we investigate the universal relations between moment of inertia and compactness in the context of a hot and young compact object.