NUMERICAL CONTINUATION OF FAMILIES OF FROZEN ORBITS IN THE ZONAL PROBLEM OF ARTIFICIAL-SATELLITE THEORY

In the zonal problem of a satellite around the Earth, we continue nume rically natural families of periodic orbits with the polar component o f the angular momentum as the parameter. We found three families; two of them are made of orbits with linear stability while the third one i s made of unstable orbits. Except in a neighborhood of the critical in clination, the stable periodic (or frozen) orbits have very small ecce ntricities even for large inclinations.