White Dwarf Critical Tests for Modified Gravity

TL;DR

This paper uses white dwarf observations to test and constrain modifications to gravity theories, providing new bounds on deviations from Newtonian gravity.

Contribution

It introduces a novel method to constrain beyond Horndeski gravity theories using white dwarf properties such as mass-radius relation and rotational limits.

Findings

White dwarfs impose stronger constraints on gravity deviations than other dwarf stars.

New bounds on the parameter psilon characterizing modified gravity.

White dwarf data improve tests of scalar-tensor theories of gravity.

Abstract

Scalar-tensor theories of gravity can lead to modifications of the gravitational force inside astrophysical objects. We exhibit that compact stars such as white dwarfs provide a unique set-up to test beyond Horndeski theories of ${\rm G}^3$ type. We obtain stringent and independent constraints on the parameter $\Upsilon$ characterizing the deviations from Newtonian gravity using the mass-radius relation, the Chandrasekhar mass limit and the maximal rotational frequency of white dwarfs. We find that white dwarfs impose stronger constraints on $\Upsilon$ than red and brown dwarfs.