The prograde C7 resonance for Earth and Mars satellite orbits

The resonance C7 is a 1:1 eccentricity (apsidal) resonance between the longitude of a satellite's pericentre and the mean longitude of the Sun. A previous paper by the author (Breiter, 1999) identified it as the strongest of the lunisolar apsidal resonances. After the reduction to a single degree of freedom, the problem is studied qualitatively for the prograde orbits around the Earth and Mars. Pitchfork, saddle-node, and saddle connection bifurcations give rise to a complicated phase flow, which may involve up to nine critical points.