Orbital stability near the (87) Sylvia system
Résumé
The main goal of our work is to study the orbital dynamics of aspacecraft near the (87) Sylvia system. Here, we consider a non-homogeneous mass distribution with a dense core inside the primaryasteroid. The Mascon gravity framework using the shaped polyhedralsource, from lightcurve data, is chosen to calculate the gravitationalfield. The zero-velocity curves show four unstable equilibrium points.In the absence of any solar or other celestial body perturbations, anumerical analysis of the orbital dynamics in the potential field ofSylvia is done to delineate the region of stable and unstable motions.In our model, the motions of the two moons of Sylvia and of thespacecraft are integrated with the classical equations of motion in thebody-fixed frame of reference. An orbit is considered stable if thevariation of its periapsis radius does not exceed a threshold value(i.e. 6 km), and the variation of its eccentricity does not exceed 0.05,although the orientation of these orbits may change. We found that thefirst stable orbit is detected at a distance of 550 km from the centreof Sylvia. No collision occurs with the central body beyond 350 km. Thecollisions with Remus occur between 300 and 900 km, while with Romulusthey occur between 900 and 1450 km. Moreover, the orbits escape from thesystem when the distance is smaller than 350 km. Finally, we found thatthe stability region around our system decreases when the initialeccentricity increases.