Solar system constraints on the Dvali-Gabadadze-Porrati braneworld theory of gravity

TL;DR

This study uses solar system data to test the Dvali-Gabadadze-Porrati (DGP) gravity model, constraining possible planetary precession and discussing the limitations of current measurements in detecting the predicted effects.

Contribution

It provides the first constraint on DGP gravity's universal precession using planetary data and highlights the importance of orbital inclination analysis.

Findings

Set an upper limit of |dw/dt| < 0.02 arcseconds per century on planetary precession.

Current data sensitivity is insufficient to detect the predicted DGP precession of 5e-4 arcseconds per century.

Ranging data between objects in the same orbital plane cannot constrain DGP effects.

Abstract

A number of proposals have been put forward to account for the observed accelerating expansion of the Universe through modifications of gravity. One specific scenario, Dvali-Gabadadze-Porrati (DGP) gravity, gives rise to a potentially observable anomaly in the solar system: all planets would exhibit a common anomalous precession, dw/dt, in excess of the prediction of General Relativity. We have used the Planetary Ephemeris Program (PEP) along with planetary radar and radio tracking data to set a constraint of |dw/dt| < 0.02 arcseconds per century on the presence of any such common precession. This sensitivity falls short of that needed to detect the estimated universal precession of |dw/dt| = 5e-4 arcseconds per century expected in the DGP scenario. We discuss the fact that ranging data between objects that orbit in a common plane cannot constrain the DGP scenario. It is only through the relative inclinations of the planetary orbital planes that solar system ranging data have sensitivity to the DGP-like effect of universal precession. In addition, we illustrate the importance of performing a numerical evaluation of the sensitivity of the data set and model to any perturbative precession.