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Speaker: Antranik Sefilian, Steward Observatory, UA
Title: Recent advances in modelling coupled dynamics of planets and exo-Kuiper belts
Abstract: In celestial mechanics, planet-disk interactions represent a canonical setting for studying coupled dynamical systems. One important example is the gravitational interaction between planets and debris disks – belts of solids orbiting Sun-like stars that are analogous to the Solar System’s asteroid and Kuiper belts. A key motivation for studying these exo-Kuiper belts is that the structures commonly observed within them, such as gaps, warps, and other asymmetries, offer unique insights into planet formation and evolution and can reveal the presence of otherwise unseen planetary companions. To extract such information reliably, however, theoretical models must be dynamically complete. A fundamental limitation of many existing approaches is that, despite observational evidence that debris disks can be relatively massive, their gravitational field is typically neglected. This omission is partly due to the high computational cost of N-body simulations and the analytical intractability of the associated equations. In this talk, I will present recent advances in modelling planet-debris disk interactions that incorporate disk self-gravity using orbit-averaged formulations well suited for long-term evolution. These developments build on the use of spatially softened gravitational potentials, enabling a computationally efficient description of gravitating particulate disks. I will then demonstrate how the resulting system of coupled ordinary differential equations, applied to different astrophysical setups, reproduces key observed disk structures such as gaps and warps. I will also discuss how including disk gravity alters, and in some cases undermines, planetary inferences derived from simplified models. Finally, I will outline possible directions for further improving models of gravitating planet-debris disk systems.