Constraining turbulence mixing strength in transitional discs with planets using SPHERE and ALMA

TL;DR

This study uses synthetic ALMA and SPHERE observations to examine how turbulence strength influences dust distribution in transitional discs with planets, constraining turbulence parameters through observational morphology.

Contribution

It demonstrates that turbulence strength significantly impacts dust morphology in transitional discs and constrains turbulence levels using combined observational data.

Findings

Turbulence parameter $\alpha_{turb}$ strongly affects dust distribution morphology.

Constrains $\alpha_{turb}$ to around $10^{-3}$ in certain transitional discs.

Dust morphology varies with turbulence, affecting cavity appearance in different wavelengths.

Abstract

We investigate the effect that the turbulent mixing strength parameter $\alpha_{\rm{turb}}$ plays on near-infrared polarimetric and sub-millimetre interferometric imaging observations of transitional discs (TDs) with a gap carved by a planet. We generate synthetic observations of these objects with ALMA and VLT/SPHERE-ZIMPOL by combining hydrodynamical, dust evolution, radiative transfer and instrument models for values of $\alpha_{\rm{turb}}=[10^{-4}, 10^{-3}, 10^{-2}]$. We find that, through a combination of effects on the viscosity of the gas, the turbulent mixing and dust evolution processes, $\alpha_{\rm{turb}}$ strongly affects the morphology of the dust distribution that can be traced with these observations. We constrain the value of $\alpha_{\rm{turb}}$ to be within an order of magnitude of $10^{-3}$ in TD sources that show cavities in sub-mm continuum images while featuring continuous distribution of dust or smaller cavities in NIR-polarimetric images.