Twin stars: probe of phase transition from hadronic to quark matter

TL;DR

This paper investigates the internal structure of hybrid compact stars undergoing a hadron to quark phase transition, exploring how such transitions can produce twin star configurations with identical masses but different radii.

Contribution

It analyzes the phase transition mechanisms in hybrid stars using Maxwell and Gibbs constructions, revealing conditions for the emergence of twin star solutions.

Findings

Mass-radius relations show distinct twin star branches.

Phase transition parameters significantly influence star stability.

Hybrid stars can have identical masses with different radii.

Abstract

In agreement with the gravitational-wave events which are constantly increasing, new aspects of the internal structure of compact stars have come to light. A scenario in which a first order transition takes place inside these stars is of particular interest as it can lead, under conditions, to a third gravitationally stable branch (besides white dwarfs and neutron stars). This is known as the twin star scenario. The new branch yields stars with the same mass as normal compact stars but quite different radii. In the current work, we focus on hybrid stars undergone a hadron to quark phase transition near their core and how this new stable configuration arises. Emphasis is to be given especially in the aspects of the phase transition and its parameterization in two different ways, namely with Maxwell construction and with Gibbs construction. Qualitative findings of mass-radius relations of these stars will also be presented.