The Two-Dimensional Structure of Circumplanetary Disks and their Radiative Signatures

TL;DR

This paper models the vertical structure and radiative signatures of circumplanetary disks, revealing their thickness, temperature, stability, and how their observational features depend on system parameters.

Contribution

It provides a self-consistent numerical model of circumplanetary disks' structure and radiative signatures, highlighting their thickness, thermal stability, and observational implications.

Findings

Disks are thick and hot with aspect ratios 0.1-0.25.

Disks are gravitationally stable under typical conditions.

Rapid accretion can cause thermal instability.

Abstract

During their formative stages, giant planets are fed by infalling material sourced from the background circumstellar disk. Due to conservation of angular momentum, the incoming gas and dust collects into a circumplanetary disk that processes the material before it reaches the central planet itself. This work investigates the complex vertical structure of these circumplanetary disks and calculates their radiative signatures. A self-consistent numerical model of the temperature and density structure of the circumplanetary environment reveals that circumplanetary disks are thick and hot, with aspect ratios $H/R\sim0.1-0.25$ and temperatures approaching that of the central planet. The disk geometry has a significant impact on the radiative signatures, allowing future observations to determine critical system parameters. The resulting disks are gravitationally stable and viscosity is sufficient to drive the necessary disk accretion. However, sufficiently rapid mass accretion can trigger a thermal instability, which sets an upper limit on the mass accretion rate. This paper shows how the radiative signatures depend on the properties of the planetary system and discuss how the system parameters can be constrained by future observations.