Correções de pressão na dinâmica de fluidos newtoniana e comparação com a teoria da Relatividade Geral

Abstract

Stellar equilibrium and cosmology are physical branches originating from one trunk, which are usually tackled using General Relativity as the background theory. However, it is possible to describe them under certain conditions using Newtonian hydrodynamics. Moreover, the validity of these equations can be extended with the introduction of a pressure term which acts as a source of gravitational field, as it happens for General Relativity. This correction has, in some instances, been put by hands, inspired by General Relativity. However, recently Hwang and Noh proposed a new set of neo-Newtonian equations. We will study the results for the Newtonian theory, neo-Newtonian and Hwang-Noh theories as well as the very general relativity applied to stars and cosmology and will compare their predictions. We will see that despite the forecast of super giant stars of neutrons in the study of stellar balance, the hydrodynamic equations of Hwang-Noh bring us in particular cases, results similar to General Relativity as the evolution of the universe.