Mass-radius bounds in massive gravity models

Abstract

The mass-radius ratio bounds of spherically symmetric static compact objects are considered in the ghost-free dRGT massive gravity. In this type of modified gravity model, the graviton has a non-zero mass leading to the naturally generated cosmological constant term. Therefore, this may bring about to an explanation for the late-time accelerated expansion of the Universe without assuming any additional dark energy. The hydrostatic equilibrium (TOV) equation in this theory is derived to describe the structure of a spherical object such as a star. In this work, the generalized Buchdahl inequalities, providing the upper and lower limits of mass-radius ratio for high density compact objects, are obtained together with their crucial constraints. Finally, for theoretical testing these results may be proved in the context of astrophysical observations.