Collège De France (général)

Alessandro MorbidelliChaire Chaire Formation planétaire : de la Terre aux exoplanètesCollège de FranceAnnée 2025-2026David NesvornýConférence - David Nesvorný : Following Comets to Their Distant Source Reservoirs and BackDavid NesvornýSouthwest Research Institute, USARésuméComets are icy bodies that originate in the trans-Neptunian region and evolve into the inner Solar System, where they become active due to the sublimation of water ice triggered by solar heating. We describe dynamical models that trace the implantation of comets into their distant source reservoirs during the early Solar System, approximately 4.6 billion years ago. These models are used to predict the present-day orbital distribution and number of active comets, which are then compared to observational data. The results indicate that the scattered disk and the Oort cloud are the primary source reservoirs for ecliptic comets (short-period) and isotropic comets (long-period and Halley-type), respectively. The observed orbital distribution of