| Chaotic diffusion in the outer solar system |
| Emese Kővári |
| ELTE, Budapest, Hungary |
| The Kuiper belt (or, in a broader sense, the trans-Neptunian space), located beyond the orbit of Neptune, provides an inexhaustible source of dynamical problems. The small bodies of the region (trans-Neptunian objects, TNOs) might seem very distant, but they are fundamental participants in the long-term dynamics of the solar system. In this sense, the key process is the chaotic diffusion, which, acting like a dynamical conveyor belt, takes part in the transportation of the TNOs and thus has the potential of reshaping the dynamical appearance of the entire system (over millions or billions of years). In the talk, I explore the most important characteristics of the chaotic diffusion in the inner part of the Kuiper belt (30-40 AU). The diffusion is quantified through an indirect method based on the MSD (mean squared displacement) of a large number of test particles. The approach allows, on the one hand, the differentiation between sub-, normal, and superdiffusion, and the determination of the characteristic diffusion (or stability) timescales of the diffusion-wise different phase space regions, on the other. The results show the protective role of the (strongest, first-order) mean-motion resonances (with slow subdiffusion and very long diffusion timescales) but reveal the location of the fastest escapees of the region as well. The indirect results are also studied in the light of an independent reference, the latter based on the direct, long-term numerical integration of real TNOs. The two approaches are in good agreement, but their comparison also highlights the need for a more complex study in the case of the non-resonant, nearly circular orbits. |