Post-Newtonian celestial mechanics in scalar-tensor cosmology
Abstract
Applying the recently developed dynamical perturbation formalism on cosmological background to scalar-tensor theory, we provide a solid theoretical basis and a rigorous justification for phenomenological models of orbital dynamics that are currently used to interpret experimental measurements of the time-dependent gravitational constant. We derive the field equations for the scalar-tensor perturbations and study their gauge freedom associated with the cosmological expansion. We find a new gauge eliminating a prohibitive number of gauge modes in the field equations and significantly simplifying post-Newtonian equations of motion for localized astronomical systems in the universe with a time-dependent gravitational constant. We identify several new post-Newtonian terms and calculate their effect on secular cosmological evolution of the osculating orbital elements.
- Publication:
-
Physical Review D
- Pub Date:
- August 2016
- DOI:
- 10.1103/PhysRevD.94.044015
- arXiv:
- arXiv:1606.09139
- Bibcode:
- 2016PhRvD..94d4015G
- Keywords:
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- General Relativity and Quantum Cosmology
- E-Print:
- 7 pages, no figures