Survival of planet-induced vortices in 2D disks

TL;DR

This study investigates the longevity of planet-induced vortices in protoplanetary disks through 2D simulations, revealing that cooling timescales, turbulence, and self-gravity significantly influence vortex survival, with some lasting over thousands of orbits.

Contribution

It provides a comprehensive analysis of how thermal relaxation, turbulence, and self-gravity affect the lifetime of vortices generated by planets in protoplanetary disks.

Findings

Vortices can survive 100-3000 planetary orbits under typical conditions.

Very low viscosity and rapid cooling can produce vortices lasting over 15,000 orbits.

Self-gravity reduces vortex lifetime but still allows for long-lived vortices.

Abstract

Context: Several observations of protoplanetary disks display non-axisymmetric features, often interpreted as vortices. Numerical modeling has repeatedly shown that gap-opening planets are capable of producing large and long-lasting vortices at their outer gap edge, making massive planets popular candidates as the source of such features. Aims: We explore the lifetime of vortices generated by Jupiter-sized planets as a function of the thermal relaxation timescale, the level of turbulence, and the effect of disk self-gravity. Methods: We conduct 2D numerical simulations using the hydrodynamics codes PLUTO and FARGO, scanning through several physical and numerical parameters. Vortex properties are automatically extracted from thousands of simulation snapshots. Results: We find that vortices that spawn at the outer gap edge can survive for about 100-3000 planetary orbits, with the shortest lifetimes occurring for moderately efficient dissipation and cooling. However, we also observe a different regime of long-lasting vortices with lifetimes of at least 15 000 orbits for very low viscosity and very short thermal relaxation timescales. Disk self-gravity significantly shortens the lifetime of regular vortices but still allows long-lived ones to survive. Conclusions: Our results suggest that the cooling timescale plays an important role in vortex formation and lifetime and that planet-generated vortices should be observable at large distances from the star for typical thermal relaxation timescales and low turbulence levels.