ON THE EFFECT OF SHORT-PERIOD TERMS IN RESONANCE TRAPPING

In this paper we study the effects of short-period perturbations in th e planar asteroidal problem with Stokes drag. The averaging of the dis sipative terms is extended to show the appearance of crossed-terms whi ch, in most commensurabilities, are more important than several zeroth -order terms calculated in previous works. In the case of resonance tr apping in a libration point, we also discuss the effects of the eccent ricity of the perturber in the stationary solution. For the so-called 'universal eccentricity', we show that the contributions due to both, short-period terms and harmonics of the auxiliary resonant angle, lead to a corrected value which is no longer invariant. The most significa nt dependence of this new librational eccentricity is with the eccentr icity of the perturber, although a slight variation is also noted with respect to the chosen drag coefficient. In all cases, we present comp arisons with numerical simulations of the exact N-body equations.