Evidence That Wide Binary Stars Are MOND-Like

A new preprint claims to observe at ten sigma significance, a deviation from Newtonian gravity consistent with MOND in wide binary stars from a sample of 26,615 stars and also appears to consider the external field effect of MOND, which is a concern previously raised about wide binary star gravitational evidence. Previous papers by other authors have questioned whether the data quality supports this conclusion. 

This would be contrary to the expectations of dark matter phenomena coming from a halo of dark matter particles and would also be contrary to Deur's gravitational field self-interaction paradigm.

A gravitational anomaly is found at weak gravitational acceleration g(N)<10^−9 m s^−2 from analyses of the dynamics of wide binary stars selected from the Gaia EDR3 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 g(N)≡GM/r2 (where M is the total mass of the binary system) and a kinematic acceleration g≡v^2/r is compared with the corresponding relation predicted by Newtonian dynamics. 

The empirical acceleration relation at <10^−9 m s^−2 systematically deviates from the Newtonian expectation. A gravitational anomaly parameter δ(obs−newt) between the observed acceleration at g(N) and the Newtonian prediction is measured to be: δ(obs−newt)=0.034±0.007 and 0.109±0.013 at g(N)≈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 g(N)=10^−10.15 m s^−2, the observed to Newton predicted acceleration ratio is g(obs)/g(pred)=10^(2√δ(obs−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.

Kyu-Hyun Chae, "Breakdown of the Newton-Einstein Standard Gravity at Low Acceleration in Internal Dynamics of Wide Binary Stars" arXiv:2305.04613 (May 8, 2023) (submitted to Apj).