Abstract

In this talk, I will present how resonant interactions between moderately eccentric planets and debris disks can indirectly lead to the production of active comets. The characteristics of this production (rates, timescales) were investigated thanks to a combination of analytical predictions and complementary numerical N-body simulations. This mechanism can lead to the production of active comets with delays of the order of several 100 Myr and can sustain continuous production of active comets over Gyr-timescales once it has started. This is extremely interesting in the context of the formation of analogues to the Solar System Zodiacal Cloud, made of short-lived hot dust residing in the immediate vicinity of a star. These have been detected around many stars, and in particular old ones (> 100 Myr). A promising scenario is that exozodis are refilled in situ through cometary activity and sublimation. As the reservoir of comets is not expected to be replenished, their presence in old systems has yet to be adequately explained. Given the characteristic timescales involved, mean-motion resonances with eccentric planets appear then to be an excellente candidate mechanism to explain the presence of exozodis around old stars. It is, in addition, a robust process which operates for a large range of planetary parameters, and through which low mass disks comparable to the Kuiper Belt could sustain comet scattering at rates compatible with the replenishement of the detected exozodis.