The exterior spacetime of relativistic stars in scalar-Gauss-Bonnet gravity (1903.07779v2)

Abstract: The spacetime around compact objects is an excellent place to study gravity in the strong, nonlinear, dynamical regime where solar system tests cannot account for the effects of large curvature. Understanding the dynamics of this spacetime is important for testing theories of gravity and probing a regime which has not yet been studied with observations. In this paper, we construct an analytical solution for the exterior spacetime of a neutron star in scalar-Gauss-Bonnet gravity that is independent of the equation of state chosen. The aim is to provide a metric that can be used to probe the strong-field regime near a neutron star and create predictions that can be compared with future observations to place possible constraints on the theory. In addition to constructing the metric, we examine a number of physical systems in order to see what deviations exist between our spacetime and that of general relativity. We find these deviations to be small and of higher post-Newtonian order than previous results using black hole solutions. The metric derived here can be used to further the study of scalar-Gauss-Bonnet gravity in the strong field, and allow for constraints on corrections to general relativity with future observations.