Hydrodynamic turbulence in disks with embedded planets

TL;DR

This study uses high-resolution simulations to explore how the vertical shear instability (VSI) causes turbulence in protoplanetary disks and how embedded planets influence this turbulence, affecting accretion and mixing.

Contribution

It demonstrates that embedded planets can suppress or coexist with VSI turbulence, depending on local disk conditions, and highlights the impact of planetary features on observable turbulence signatures.

Findings

VSI contributes to accretion stress in disks.

Embedded planets can suppress or coexist with VSI turbulence.

Spiral shocks and vortices interfere with VSI near planets.

Abstract

The vertical shear instability (VSI) is a source of hydrodynamic turbulence that can drive vigorous vertical mixing and moderate levels of accretion in protoplanetary disks, and it could be observable in the near future. With high-resolution three-dimensional numerical hydrodynamics simulations, we modeled the behavior of the VSI in protoplanetary disks with and without embedded planets. We then measured its accretion and mixing capabilities by comparing the full Reynolds stress, which includes the contribution of nonaxisymmetric features, such as spiral arms and vortices, to the Reynolds stress due to the azimuthally averaged velocity field, which can be attributed to good approximation to the VSI. We verified that the VSI can contribute to the accretion stress and showed that, depending on disk conditions, an embedded planet can coexist with or suppress VSI turbulent stress. Specifically, the presence of spiral shocks launched by a planet or planet-generated vortices can interfere with the VSI near the planet's vicinity, with the instability recovering at large enough distances from the planet or vortex. Our results suggest that observations of VSI signatures are unlikely in disks that contain massive, nonaxisymmetric features.