Transiting planets as a precision clock to constrain the time variation of the gravitational constant

TL;DR

This study uses long-term transit timing data from Kepler to set constraints on the possible variation of the gravitational constant G over time, providing a complementary method to existing tests.

Contribution

It applies transit timing analysis to multiple exoplanet systems to derive new limits on the time variation of G, demonstrating the potential of exoplanet data for fundamental physics tests.

Findings

Limit on ΔG/G is approximately 5×10^{-6} for 2009-2013.

Constraint on the rate of change of G is about 10^{-6} per year.

Method is complementary to other existing constraints.

Abstract

Analysis of transit times in exoplanetary systems accurately provides an instantaneous orbital period, $P(t)$, of their member planets. A long-term monitoring of those transiting planetary systems puts limits on the variability of $P(t)$, which are translated into the constraints on the time variation of the gravitational constant $G$. We apply this analysis to $10$ transiting systems observed by the Kepler spacecraft, and find that $\Delta G/G\lesssim 5\times10^{-6}$ for 2009-2013, or $\dot{G}/G \lesssim 10^{-6}\,\mathrm{yr}^{-1}$ if $\dot{G}$ is constant. While the derived limit is weaker than those from other analyses, it is complementary to them and can be improved by analyzing numerous transiting systems that are continuously monitored.