Building approximate stellar models in general relativity

Abstract

[EN] We build and study rotating and time-independent stellar models in General Relativity using analytical approximations (post-Minkowskian and slow rotation) for a perfect fluid with linear equation of state and some of its subcases, including in particular uniform density, the one of the Wahlquist’s and Whitakker’s solutions fluid and MIT bag model strange matter. We obtain a global spacetime matching the interior solution (inside the source) to an asymptotically flat exterior using both Lichnerowicz and Darmois-Israel matching conditions. Concerning the interior, we find its possible Petrov types and cast it into the same form a certain perturbative expansion of Wahlquist’s solution has. We also use the AKM numerical code to obtain equivalent models to compare both the metric components and the results for many physical properties of the source we obtain from analytical formulae, getting good results from the comparison. Finally, we increase the complexity and adaptability of the interior adding an additional layer of linear EOS matter. [ES] el espectro completo de estrellas compactas degeneradas se puede modelar con capas de polítropo y EOS de modelo de bolsa del MIT, los cuales están dentro de los tipos de métrica obtenidos por ahora con CMMR. En el caso particular de estrellas extrañas con corteza, sólo harían falta dos capas. Se podría pensar que para estrellas de baja masa la corteza es demasiado fina como para que realmente merezca la pena, pero se deforma más fácilmente que la SQM a velocidades angulares altas y puede ser de importancia en la medida de la ISCO