Estabilidade de estrelas híbridas sob diferentes velocidades de conversão de fase e configurações de carga

Abstract

The debate on the internal composition of neutron stars remains in constant evolution. Quantum Chromodynamics, the theory of strong interactions, still fails to provide an accurate description of the high densities found in these stars, especially in their cores. Consequently, the equation of state modeling the composition of these stars remains inaccurate. Recently, both theoretical and observational efforts have been made to reduce this uncertainty, through precise observations of the mass and radius of neutron stars. A common hypothesis in the literature is the existence of a phase transition in their interior, giving rise to so-called hybrid stars, composed of a core of strange quark matter surrounded by a hadronic mantle. However, the order and speed of this transition are still unknown. In this study, we assume the hypothesis that neutron stars are hybrid stars, with a first-order phase transition, following Maxwell’s construction. To analyze the stability of these objects, we will use the formalism of radial oscillations from the theory of General Relativity. Additionally, we will examine the speed of conversion between the hadronic and quark phases, comparing it with the radial oscillations of the star, which directly influences its stability. Furthermore, we will treat, in a part of this dissertation, the effects of the presence of electric charge in the structure and stability of twin stars. This study aims to contribute to advancing the understanding of the phase transition in neutron stars and how the mentioned modifications affect their stability and structure.