A new helioseismic constraint on a cosmic-time variation of G

TL;DR

Helioseismology data constrains the current rate of change of Newton's gravitational constant G, revealing a significant variation over cosmic time with improved precision over previous methods.

Contribution

This study provides the first strong Bayesian constraint on the time variation of G using helioseismic data, surpassing previous limits by over an order of magnitude.

Findings

Measured b7G/Gb7_{\rm today}}=(1.25\u00b1 0.30) imes 10^{-13} yr^{-1}

Detected a 4- sigma effect indicating G varies over cosmic time

Models with variable G are strongly favored over constant G models with a Bayes factor exceeding 30.

Abstract

Helioseismology can provide strong constraints on the evolution of Newton's constant over cosmic time. We make use of the best possible estimate of 8640 days of low-$\ell$ BISON data, corrected for the solar cycle variation, to obtain a new constraint on an evolving gravitational constant. In particular, by means of a Bayesian analysis we conclude that ${{\dot{G}/G}_{\rm today}}=(1.25\pm 0.30) \times 10^{-13} \; \mathrm{yr}^{-1}$. Our result, a 4-$\sigma$ effect, is more than one order of magnitude stronger than previous constraints obtained with helioseismology. We also take into account possible systematic effects by considering the theoretical uncertainties on the efficiency of the proton-proton $(pp)$ fusion cross-section. We show that models with variable $G$ significantly outclass models with no secular variation of $G$, viz by a Bayes factor exceeding 30.