An independent constraint on the secular rate of variation of the gravitational constant from pulsating white dwarfs

TL;DR

This paper uses pulsating white dwarfs to set constraints on the possible secular variation of Newton's gravitational constant, G, by comparing theoretical models with observed pulsation period changes.

Contribution

It introduces a novel method to constrain the variation of G using pulsating white dwarfs and provides new upper bounds based on observational data.

Findings

Upper bound on G variation from G117--B15A: -1.8×10^{-10} yr^{-1}

Upper bound from R548: -1.3×10^{-10} yr^{-1}

Method can be improved with future measurements of massive white dwarfs.

Abstract

A secular variation of the gravitational constant modifies the structure and evolutionary time scales of white dwarfs. Using an state-of-the-art stellar evolutionary code and an up-to-date pulsational code we compute the effects of a secularly varying $G$ on the pulsational properties of variable white dwarfs. Comparing the the theoretical results obtained taking into account the effects of a running $G$ with the observed periods and measured rates of change of the periods of two well studied pulsating white dwarfs, G117--B15A and R548, we place constraints on the rate of variation of Newton's constant. We derive an upper bound $\dot G/G\sim -1.8\times 10^{-10}$ yr$^{-1}$ using the variable white dwarf G117--B15A, and $\dot G/G\sim -1.3\times 10^{-10}$ yr$^{-1}$ using R548. Although these upper limits are currently less restrictive than those obtained using other techniques, they can be improved in a future measuring the rate of change of the period of massive white dwarfs.