Planet-induced disk structures: A comparison between (sub)mm and infrared radiation

TL;DR

This study explores the potential to observe planet-induced gaps in circumstellar disks using scattered light, comparing it with (sub)mm thermal emission, and finds detection feasible mainly in low-mass disks.

Contribution

It provides a comparative analysis of gap detectability in scattered light versus (sub)mm emission through 3D simulations, highlighting conditions for successful observation.

Findings

Gap detection in scattered light is feasible in low-mass disks below ~10^{-4} M_sun.

Detection in both scattered light and thermal emission occurs in about 16% of cases within a specific mass range.

Disk optical depth and size critically influence the observability of planet-induced gaps.

Abstract

Young giant planets, which are embedded in a circumstellar disk, will significantly perturb the disk density distribution. This effect can potentially be used as an indirect tracer for planets. We investigate the feasibility of observing planet-induced gaps in circumstellar disks in scattered light. We perform 3D hydrodynamical disk simulations combined with subsequent radiative transfer calculations in scattered light for different star, disk, and planet configurations. The results are compared to those of a corresponding study for the (sub)mm thermal re-emission. The feasibility of detecting planet-induced gaps in scattered light is mainly influenced by the optical depth of the disk and therefore by the disk size and mass. Planet-induced gaps are in general only detectable if the photosphere of the disks is sufficiently disturbed. Within the limitations given by the parameter space here considered, we find that gap detection is possible in the case of disks with masses below $\sim 10^{-4\dots-3} \, \rm M_\odot$. Compared to the disk mass that marks the lower Atacama Large (Sub)Millimeter Array (ALMA) detection limit for the thermal radiation re-emitted by the disk, it is possible to detect the same gap both in re-emission and scattered light only in a narrow range of disk masses around $\sim 10^{-4} \, \rm M_\odot$, corresponding to $16\%$ of cases considered in our study.