Repulsion Between Two Super-Earths Due to Wave Planet Interactions

Zijia Cui, John C. B. Papaloizou and Ewa Szuszkiewicz

We study the orbital evolution of a system of two super-Earths embedded in a protoplanetary disk close to a first order resonance. We focus on a repulsion mechanism connected to wave planet interactions. This works through angular momentum carried by waves emitted by one planet being transferred to the vicinity of the other planet and subsequently to it through horseshoe drag.

From hydrodynamical simulations, we found that the initial convergent migration of two super-Earths is converted to become divergent, when approaching first order resonances, thus preventing the system from becoming locked into them. We give approximate conditions for a planet to be effectively repelled due to the wave planet repulsion mechanism. These imply that the planet should be able to form a partial gap in the disk and there should be enough material in it to enable angular momentum to be efficiently transferred to the associated planet through horseshoe drag. The numerical simulations indicate that when these conditions for the wave planet repulsion mechanism are satisfied, divergent migration occurs thus preventing capture into resonance.

Proceedings of the Polish Astronomical Society, vol. 12, 260-265 (2022)

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