Kinematic Structures in Planet-Forming Disks

TL;DR

Recent high-resolution observations have revealed complex dynamical structures in planet-forming disks, providing insights into the physical processes and planet formation mechanisms through kinematic studies.

Contribution

This paper reviews recent advances in understanding disk dynamics and emphasizes the role of kinematic mapping in observing planet formation processes.

Findings

Detection and mass measurement of embedded planets

Mapping of gas flows around accreting planets

Constraints on turbulence and disk geometries

Abstract

The past 5 years have dramatically changed our view of the disks of gas and dust around young stars. Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) and extreme adaptive optics systems have revealed that disks are dynamical systems. Most disks contain resolved structures, both in gas and dust, including rings, gaps, spirals, azimuthal dust concentrations, shadows cast by misaligned inner disks, as well as deviations from Keplerian rotation. The origin of these structures and how they relate to the planet formation process remain poorly understood. Spatially resolved kinematic studies offer a new and necessary window to understand and quantify the physical processes (turbulence, winds, radial and meridional flows, stellar multiplicity, instabilities) at play during planet formation and disk evolution. Recent progress, driven mainly by resolved ALMA observations, includes the detection and mass determination of embedded planets, the mapping of the gas flow around the accreting planets, the confirmation of tidal interactions and warped disk geometries, and stringent limits on the turbulent velocities. In this chapter, we will review our current understanding of these dynamical processes and highlight how kinematic mapping provides new ways to observe planet formation in action.