Structure of compact stars in Palatini f (R) gravity

Abstract

The study of the structure of compact objects in modified theories of gravity can be useful to constrain f (R)-theories in the strong gravitational regime. In particular, the structure of compact stars in the theory with Langrangian density f (R) = R + αR2 have been recently explored using the metric formalism. In this work we analyze configurations of neutron stars in squared-gravity using the Palatini formalism, in which the field equations are of second order, and the modified Tolman-Oppenheimer-Volkoff equations for a sphericallysymmetric and static metric can be derived without approximation, as in General Relativity. The numerical integration of the structure equations allows us to study the mass-radius configurations and the characteristics of internal profiles. We compare our results with those obtained using General Relativity.