Secular Dynamics for Curved Two-Body Problems.

Consider the dynamics of two point masses on a surface of constant curvature subject to an attractive force analogue of Newton's inverse square law, that is under a 'cotangent' potential. When the distance between the bodies is sufficiently small, the reduced equations of motion may be seen as a perturbation of an integrable system. We take suitable action-angle coordinates to average these perturbing terms and describe dynamical effects of the curvature on the motion of the two-bodies. [ABSTRACT FROM AUTHOR]