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Bibliographic Details
Main Authors: Mariani, Mauro, Ranea-Sandoval, Ignacio F.
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2602.06170
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author Mariani, Mauro
Ranea-Sandoval, Ignacio F.
author_facet Mariani, Mauro
Ranea-Sandoval, Ignacio F.
contents Multi-messenger astronomical observations of neutron stars, together with more precise calculations and constraints coming from dense matter microphysics, are generating tension with regard to equations of state models used to describe neutron star cores. Assuming an abrupt first-order phase transition with a slow conversion speed between phases, we propose different slow stable hybrid star configurations aiming to reconcile all current constraints simultaneously; within this framework, we also introduce a novel non-CSS parametrization to the quark matter equation of state and discuss its strengths and limitations. We analyze our model results in conjunction with a review of other relevant theoretical possibilities existing in the literature. We found that modern neutron star observations seem to favor the existence of some type of exotic matter in the neutron star cores; in particular, our slow stable hybrid star scenario remains a proposal capable of satisfying these constraints. However, due both to the existing skepticism regarding some of the adopted hypotheses in most extreme neutron star measurements and to the precise adjustment needed for the equation-of-state parameters, significant tension and open questions remain.
format Preprint
id arxiv_https___arxiv_org_abs_2602_06170
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle How Neutron Star Observations Point Towards Exotic Matter: Existing Explanations and a Prospective Proposal
Mariani, Mauro
Ranea-Sandoval, Ignacio F.
High Energy Astrophysical Phenomena
Nuclear Theory
Multi-messenger astronomical observations of neutron stars, together with more precise calculations and constraints coming from dense matter microphysics, are generating tension with regard to equations of state models used to describe neutron star cores. Assuming an abrupt first-order phase transition with a slow conversion speed between phases, we propose different slow stable hybrid star configurations aiming to reconcile all current constraints simultaneously; within this framework, we also introduce a novel non-CSS parametrization to the quark matter equation of state and discuss its strengths and limitations. We analyze our model results in conjunction with a review of other relevant theoretical possibilities existing in the literature. We found that modern neutron star observations seem to favor the existence of some type of exotic matter in the neutron star cores; in particular, our slow stable hybrid star scenario remains a proposal capable of satisfying these constraints. However, due both to the existing skepticism regarding some of the adopted hypotheses in most extreme neutron star measurements and to the precise adjustment needed for the equation-of-state parameters, significant tension and open questions remain.
title How Neutron Star Observations Point Towards Exotic Matter: Existing Explanations and a Prospective Proposal
topic High Energy Astrophysical Phenomena
Nuclear Theory
url https://arxiv.org/abs/2602.06170