Modified gravity at astrophysical scales

Abstract

Using a perturbative approach we solve stellar structure equations for low-density (solar-type) stars whose interior is described with a polytropic equation of state in scenarios involving a subset of modified gravity (MG) theories. Rather than focusing on particular theories, we consider a model-independent approach in which deviations from General Relativity are effectively described by a single parameter xi. We find that for length scales below those set by stellar General Relativistic radii the modifications introduced by MG can affect the computed values of masses and radii. As a consequence, the stellar luminosity is also affected. We discuss possible further implications for higher-density stars and observability of the effects previously described.