Breakdown of the Newton-Einstein Standard Gravity at Low Acceleration in Internal Dynamics of Wide Binary Stars

A gravitational anomaly is found at weak gravitational acceleration gN<10−9 m s−2 from analyses of the dynamics of wide binary stars selected from the Gaia DR3 database that have accurate distances, proper motions, and reliably inferred stellar masses. Implicit high-order multiplicities are required and the multiplicity fraction is calibrated so that binary internal motions agree statistically with Newtonian dynamics at a high enough acceleration of 10−8 m s−2. The observed sky-projected motions and separation are deprojected to the three-dimensional relative velocity v and separation r through a Monte Carlo method, and a statistical relation between the Newtonian acceleration gN≡GM/r2 (where M is the total mass of the binary system) and a kinematic acceleration g≡v2/r is compared with the corresponding relation predicted by Newtonian dynamics. The empirical acceleration relation at less than 10^−9 m s−2 systematically deviates from the Newtonian expectation. A gravitational anomaly parameter δobs−newt between the observed acceleration at gN and the Newtonian prediction is measured to be: δobs−newt=0.034±0.007 and 0.109±0.013 at gN≈10−8.91 and 10−10.15 m s−2, from the main sample of 26,615 wide binaries within 200 pc. These two deviations in the same direction represent a 10σ significance. The deviation represents a direct evidence for the breakdown of standard gravity at weak acceleration. At gN=10−10.15 m s−2, the observed to Newton predicted acceleration ratio is gobs/gpred=102√δobs−newt=1.43±0.06. This systematic deviation agrees with the boost factor that the AQUAL theory predicts for kinematic accelerations in circular orbits under the Galactic external field.
http://arxiv.org/abs/2305.04613