1/1/1 RESONANT PERIODIC-ORBITS IN 3-DIMENSIONAL GALACTIC-TYPE HAMILTONIANS

Using a semi-numerical method we find the position and frequency of several types of periodic orbits, in galactic type 3-dimensional Hamiltonian systems, in the 1:1:1 resonance. Our results are compared with those given by numerical integration of the equations of motion. It is found that, when the maximum perturbation is less or equal to about 10% of the unperturbed Hamiltonian, the agreement is good.