Testing Gravity Theories Using Stars
Abstract
Modified theories of gravity have received a renewed interest due to their ability to account for the cosmic acceleration. In order to satisfy the solar system tests of gravity, these theories need to include a screening mechanism that hides the modifications on small scales. One popular and well-studied theory is chameleon gravity. Our own galaxy is necessarily screened, but less dense dwarf galaxies may be unscreened and their constituent stars can exhibit novel features. In particular, unscreened stars are brighter, hotter and more ephemeral than screened stars in our own galaxy. They also pulsate with a shorter period. In this essay, we exploit these new features to constrain chameleon gravity to levels three orders of magnitude lower the previous measurements. These constraints are currently the strongest in the literature.
Keywords
Cite
@article{arxiv.1409.3708,
title = {Testing Gravity Theories Using Stars},
author = {Jeremy Sakstein and Bhuvnesh Jain and Vinu Vikram},
journal= {arXiv preprint arXiv:1409.3708},
year = {2014}
}
Comments
This essay received an honourable mention by the Gravity Research Foundation's Awards for Essays 2014 under the title "Detecting Modified Gravity in the Stars". This version has been expanded to contain a brief discussion of the prospects for testing gravity using a binary system