ON THE FAMILIES OF PERIODIC-ORBITS WHICH BIFURCATE FROM THE CIRCULAR SITNIKOV MOTIONS

In this paper we deal with the circular Sitnikov problem as a subsyste m of the three-dimensional circular restricted three-body problem. It has a first analytical part where by using elliptic functions we give the analytical expressions for the solutions of the circular Sitnikov problem and for the period function of its family of periodic orbits. We also analyze the qualitative and quantitative behavior of the perio d function. In the second numerical part, we study the linear stabilit y of the family of periodic orbits of the Sitnikov problem, and of the families of periodic orbits of the three-dimensional circular restric ted three-body problem which bifurcate from them; and we follow these bifurcated families until they end in families of periodic orbits of t he planar circular restricted three-body problem. We compare our resul ts with the previous ones of other authors on this problem. Finally, t he characteristic curves of some bifurcated families obtained for the mass parameter close to 1/2 are also described.