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

Department of Theoretical Physics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece

^* e-mail: tdeloudi@physics.auth.gr
^** e-mail: pkoliogi@physics.auth.gr
^*** e-mail: moustaki@auth.gr

Published online: 10 September 2021

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 parametrization 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.