On shocks driven by high-mass planets in radiatively inefficient disks. I. Two-dimensional global disk simulations

TL;DR

This study uses two-dimensional hydrodynamical simulations to explore how high-mass planets induce shocks and turbulence in radiatively inefficient disks, revealing effects that better match observed disk structures than previous isothermal models.

Contribution

It introduces detailed 2D simulations of massive planet-disk interactions considering non-isothermal effects, highlighting shock heating and turbulence impacts on disk morphology.

Findings

Massive planets (>5 M_jup) induce shock heating and turbulence.

Spiral structures in heated disks better match observations.

Disruption of typical planet-disk features in adiabatic conditions.

Abstract

Recent observations of gaps and non-axisymmetric features in the dust distributions of transition disks have been interpreted as evidence of embedded massive protoplanets. However, comparing the predictions of planet-disk interaction models to the observed features has shown far from perfect agreement. This may be due to the strong approximations used for the predictions. For example, spiral arm fitting typically uses results that are based on low-mass planets in an isothermal gas. In this work, we describe two-dimensional, global, hydrodynamical simulations of disks with embedded protoplanets, with and without the assumption of local isothermality, for a range of planet-to-star mass ratios 1-10 M_jup for a 1 M_sun star. We use the Pencil Code in polar coordinates for our models. We find that the inner and outer spiral wakes of massive protoplanets (M>5 M_jup) produce significant shock heating that can trigger buoyant instabilities. These drive sustained turbulence throughout the disk when they occur. The strength of this effect depends strongly on the mass of the planet and the thermal relaxation timescale; for a 10 M_jup planet embedded in a thin, purely adiabatic disk, the spirals, gaps, and vortices typically associated with planet-disk interactions are disrupted. We find that the effect is only weakly dependent on the initial radial temperature profile. The spirals that form in disks heated by the effects we have described may fit the spiral structures observed in transition disks better than the spirals predicted by linear isothermal theory.