On the Orbits of the Milky-Way Satellites in the Local Group

S. Ninkovic1, Z. Catovic2
1 Astronomical Observatory, Volgina 7, 11160 Beograd 74, Yugoslavia < sninkovic@aob.aob.bg.ac.yu >
2 University of Belgrade, Faculty of Mathematics, Studentski trg 16, 11000 Beograd, Yugoslavia

By representing the potentials within the Milky Way and the Andromeda Nebula through a Plummer-type formula, the authors study the motion of a satellite of the Milky Way taking into account the perturbations resulting from the presence of the Andromeda Nebula. The time scale of the problem is determined by the motion of the Andromeda Nebula with respect to the Milky Way, assumed here as independent of the satellite. We find the stability limits for a satellite as a function of its basic orbit parameters such as the apogalactic distance, the eccentricity, the inclination and the initial phase.