Wide binaries as a critical test of Classical Gravity

TL;DR

This study tests modified gravity theories by analyzing wide binary star systems, finding velocity patterns consistent with theories that modify Newtonian dynamics at low accelerations, challenging traditional gravity models.

Contribution

It provides empirical evidence supporting modified gravity theories by analyzing wide binaries, revealing velocity behaviors that deviate from Newtonian expectations at large separations.

Findings

Constant upper limit to relative velocities independent of separation

Velocity patterns analogous to galactic rotation curves

Evidence of breakdown of Kepler's third law at large scales

Abstract

Modified gravity scenarios where a change of regime appears at acceleration scales $a<a_{0}$ have been proposed. Since for $1 M_{\odot}$ systems the acceleration drops below $a_{0}$ at scales of around 7000 AU, a statistical survey of wide binaries with relative velocities and separations reaching $10^{4}$ AU and beyond should prove useful to the above debate. We apply the proposed test to the best currently available data. Results show a constant upper limit to the relative velocities in wide binaries which is independent of separation for over three orders of magnitude, in analogy with galactic flat rotation curves in the same $a<a_{0}$ acceleration regime. Our results are suggestive of a breakdown of Kepler's third law beyond $a \approx a_{0}$ scales, in accordance with generic predictions of modified gravity theories designed not to require any dark matter at galactic scales and beyond.