Characterisation of chaos and mean-motion resonances in meteoroid streams

Abstract

Context. Dynamically linking a meteor shower with its parent body is challenging, and chaos in the dynamics of meteoroid streams may contribute to this challenge. For a robust identification of parent bodies, it is therefore necessary to quantify the amount of chaos involved in the evolution of meteoroid streams. Aims. Characterising chaos in meteoroid streams through the aid of chaos maps is still a new field of study. Thus, we examine two very different meteoroid streams, the Draconids and the Leonids, in order to obtain a general view of this topic. Methods. We used the method developed in a previous paper dedicated to Geminids, drawing chaos maps with the orthogonal fast Lyapunov indicator. We chose four particle size ranges to investigate the effect of non-gravitational forces. As the dynamics are structured by mean-motion resonances with planets, we computed the locations and widths of the resonances at play. We used semi-analytical formulas valid for any eccentricity and inclination and an arbitrary number of planets. Results. We pinpoint which mean-motion resonances with Jupiter play a major role in the dynamics of each meteoroid stream. We show how those resonances tend to trap mostly large particles, preventing them from meeting with Jupiter. We also study particles that manage to escape those resonances, for example, due to the gravitational perturbation of Saturn. Finally, we explain why non-gravitational forces do not disturb the dynamics much, contrary to what is observed for the Geminids.