Phase portraits of the full secular Hamiltonian (16) in space for particles trapped in 7:1 (left) and 8:1 (right) MMRs with β Pic c having negligible resonant libration amplitude, taking into account perturbations by β Pic b and General Relativity (see text). The horizontal bars denote the location of orbits with specific periastron values, down to the stellar surface (1 R_*).