Understanding Gap Formation in Protoplanetary Discs

Recent research by Amelia J. Cordwell and Roman R. Rafikov, titled "Early stages of gap opening by planets in protoplanetary discs," explores the dynamics of protoplanetary discs and how planets influence their structure. The study focuses on the gravitational interactions between embedded planets and the surrounding disc material, which can lead to the formation of gaps within these discs.

The authors detail how planetary density waves can inject angular momentum into the disc, resulting in gap formation after traveling a certain distance and steepening into shocks. Notably, they highlight that even in inviscid discs, mass evacuation occurs from the coorbital region, leading to smooth, double-trough gap profiles.

A significant finding of this research is the identification of a time-dependent contribution to the angular momentum balance, which is often overlooked. This contribution arises from the variability of the specific angular momentum of the disc fluid, influenced by radial pressure support changes. The authors demonstrate that early gap opening is a self-similar process, with the amplitude of the planet-driven perturbation growing linearly over time.

The implications of these findings are substantial for understanding the evolution of protoplanetary discs and the formation of planetary systems. The results can aid in studies of dust dynamics near planets and enhance the interpretation of observational data from protoplanetary discs. For further details, the paper can be accessed at arXiv:2407.01728.