Wide Binaries and Modified Gravity (MOG)

Abstract

Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field $G=G_N(1+\alpha)$, where $G_N$ is Newton's constant, and the massive (spin-1 graviton) vector field $\phi_\mu$. The wide binaries have separations of 2-30 kAU. The MOG acceleration law, derived from the MOG field equations and equations of motion of a massive test particle for weak gravitational fields, depends on the enhanced gravitational constant $G=G_N(1+\alpha)$ and the effective running mass $\mu$. The magnitude of $\alpha$ depends on the physical length scale or averaging scale $\ell$ of the system. The modified MOG acceleration law for weak gravitational fields predicts that for the solar system and for the wide binary star systems gravitational dynamics follows Newton's law.