TESTING ALTERNATIVE THEORIES OF GRAVITY USING THE SUN

We propose a new approach to test possible corrections to Newtonian gravity using solar physics. The high accuracy of current solar models and new precise observations allow us to constrain corrections to standard gravity at unprecedented levels. Our case study is Eddington-inspired gravity, an attractive modified theory of gravity which results in non-singular cosmology and collapse. The theory is equivalent to standard gravity in vacuum, but it sensibly differs from it within matter. For instance, it affects the evolution and the equilibrium structure of the Sun, giving different core temperature profiles, and deviations in the observed acoustic modes and in solar neutrino fluxes. Comparing the predictions from a modified solar model with observations, we constrain the coupling parameter of the theory, vertical bar K-g vertical bar less than or similar to 3 x 10(5) m(5) s(-2) kg(-1). Our results show that the Sun can be used to efficiently constrain alternative theories of gravity.