Strange quark stars: the role of excluded volume effects

Fuente: arXiv
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Main Authors: Lugones, G., Grunfeld, A. G.
Format: Preprint
Published: 2024
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author Lugones, G.
Grunfeld, A. G.
author_facet Lugones, G.
Grunfeld, A. G.
contents We study cold strange quark stars employing an enhanced version of the quark-mass density-dependent model which incorporates excluded volume effects to address non-perturbative QCD repulsive interactions. We provide a comparative analysis of our mass formula parametrization with previous models from the literature. We identify the regions within the parameter space where three-flavor quark matter is more stable than the most tightly bound atomic nucleus (stability window). Specifically, we show that excluded volume effects do not change the Gibbs free energy per baryon at zero pressure, rendering the stability window unaffected. The curves of pressure versus energy density exhibit various shapes -- convex upward, concave downward, or nearly linear -- depending on the mass parametrization. This behavior results in different patterns of increase, decrease, or constancy in the speed of sound as a function of baryon number density. We analyze the mass-radius relationship of strange quark stars, revealing a significant increase in maximum gravitational mass and a shift in the curves towards larger radii as the excluded volume effect intensifies. Excluded volume effects render our models compatible with all modern astrophysical constraints, including the properties of the recently observed low-mass compact object HESSJ1731.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18249
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strange quark stars: the role of excluded volume effects
Lugones, G.
Grunfeld, A. G.
Nuclear Theory
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
High Energy Physics - Phenomenology
We study cold strange quark stars employing an enhanced version of the quark-mass density-dependent model which incorporates excluded volume effects to address non-perturbative QCD repulsive interactions. We provide a comparative analysis of our mass formula parametrization with previous models from the literature. We identify the regions within the parameter space where three-flavor quark matter is more stable than the most tightly bound atomic nucleus (stability window). Specifically, we show that excluded volume effects do not change the Gibbs free energy per baryon at zero pressure, rendering the stability window unaffected. The curves of pressure versus energy density exhibit various shapes -- convex upward, concave downward, or nearly linear -- depending on the mass parametrization. This behavior results in different patterns of increase, decrease, or constancy in the speed of sound as a function of baryon number density. We analyze the mass-radius relationship of strange quark stars, revealing a significant increase in maximum gravitational mass and a shift in the curves towards larger radii as the excluded volume effect intensifies. Excluded volume effects render our models compatible with all modern astrophysical constraints, including the properties of the recently observed low-mass compact object HESSJ1731.
title Strange quark stars: the role of excluded volume effects
topic Nuclear Theory
High Energy Astrophysical Phenomena
Solar and Stellar Astrophysics
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2405.18249