A stellar constraint on Eddington-inspired Born-Infeld gravity from cataclysmic variable binaries

TL;DR

This paper uses observations of cataclysmic variable binaries to place constraints on Eddington-inspired Born-Infeld gravity, a modified gravity theory, by analyzing stellar observables affected by the theory's deviations from general relativity.

Contribution

It provides the first astrophysical constraint on Eddington-inspired Born-Infeld gravity using binary star data and a numerical scheme to compare theoretical predictions with observations.

Findings

Constrained the theory within 5σ confidence level.

Demonstrated the impact of modified gravity on stellar observables.

Used Monte Carlo method for error analysis.

Abstract

Eddington-inspired Born-Infeld gravity is an important modification of Einstein's general relativity, which can give rise to non-singular cosmologies at the classical level, and avoid the end-stage singularity in a gravitational collapse process. In the Newtonian limit, this theory gives rise to a modified Poisson's equation, as a consequence of which stellar observables acquire model dependent corrections, compared to the ones computed in the low energy limit of general relativity. This can in turn be used to establish astrophysical constraints on the theory. Here, we obtain such a constraint using observational data from cataclysmic variable binaries. In particular, we consider the tidal disruption limit of the secondary star by a white dwarf primary. The Roche lobe filling condition of this secondary star is used to compute stellar observables in the modified gravity theory in a numerical scheme. These are then contrasted with the values obtained by using available data on these objects, via a Monte Carlo error progression method. This way, we are able to constrain the theory within $5\sigma$ confidence level.