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Third post-Newtonian dynamics of compact binaries: Equations of motion in the center-of-mass frame

Luc Blanchet·Bala Iyer
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Abstract

The equations of motion of compact binary systems and their associated Lagrangian formulation have been derived in previous works at the third post-Newtonian (3PN) approximation of general relativity in harmonic coordinates. In the present work we investigate the binary's relative dynamics in the center-of-mass frame (center of mass located at the origin of the coordinates). We obtain the 3PN-accurate expressions of the center-of-mass positions and equations of the relative binary motion. We show that the equations derive from a Lagrangian (neglecting the radiation reaction), from which we deduce the conserved center-of-mass energy and angular momentum at the 3PN order. The harmonic-coordinates center-of-mass Lagrangian is equivalent, {\it via} a contact transformation of the particles' variables, to the center-of-mass Hamiltonian in ADM coordinates that is known from the post-Newtonian ADM-Hamiltonian formalism. As an application we investigate the dynamical stability of circular binary orbits at the 3PN order.

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Luc Blanchet, Bala Iyer. 2003-01-14. Third post-Newtonian dynamics of compact binaries: Equations of motion in the center-of-mass frame. https://doi.org/10.1088/0264-9381%2F20%2F4%2F309

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