RésuméThis thesis has taken on several subjects related to the orbital dynamics of space debris and rotational dynamics of asteroids. Space debris have received a considerable attention in recent years due to the threat they pose to active satellites and manned missions. As a result, smaller and smaller perturbations are taken into account for precise orbit determination. The Yarkovsky-Schach effect is an example of such small perturbation. We have performed numerical simulations with the ef- fect with various initial conditions. The force relative significance is only revealed over long timescales. Furthermore, we also considered the motion of an object un- der the tesseral and lunisolar resonances. With the application of a variational chaos indicator, MEGNO, several stability maps were constructed and compared with lit- erature. Some stable structures were singled out and discussed. A related problem of numerical integration issues in case of chaotic orbits was also examined. If a nu- merical integrator with a fixed time step is used, several observables are shown to be
inaccurately computed, and to depend on the chosen time step. Lastly, in case of as- teroids, we investigated the question of stability of principal axis rotation under the YORP torque and inelastic energy dissipation. We developed an approximate model for small departures from the principal axis in nutation angle and searched for condi- tions that should be met so that the instantaneous rotation axis is driven back to the stable position.
|la date de réponse||10 sept. 2019|
|Superviseur||Anne LEMAITRE (Promoteur), ANNE-SOPHIE LIBERT (Président), Slawomir BREITER (Jury), Daniel Casanova Ortega (Jury) & D. Hestroffer (Jury)|