The Substructures in Disks undergoing Vertical Shear Instability: II. Observational Predictions for the Dust Continuum

TL;DR

This paper predicts observable dust substructures in protoplanetary disks caused by vertical shear instability, providing a new perspective beyond planet-induced features, and offers guidance for future high-resolution observations.

Contribution

It introduces high-resolution 3D radiative hydrodynamical models focusing on vertical shear instability, expanding understanding of disk substructures independent of planet formation.

Findings

Dust substructures match some observed shallow gaps.

Predictions for future ALMA and ngVLA observations.

Substructures can form before planet formation.

Abstract

High-angular resolution observations at sub-millimeter/millimeter wavelengths of disks surrounding young stars have shown that their morphology is made of azimuthally-symmetric or point-symmetric substructures, in some cases with spiral arms, localized spur- or crescent-shaped features. The majority of theoretical studies with the aim of interpreting the observational results have focused on disk models with planets, under the assumption that the disk substructures are due to the disk-planet interaction. However, so far only in very few cases exoplanets have been detected in these systems. Furthermore, some substructures are expected to appear \textit{before} planets form, as they are necessary to drive the concentration of small solids which can lead to the formation of planetesimals. In this work we present observational predictions from high-resolution 3D radiative hydrodynamical models which follow the evolution of gas and solids in a protoplanetary disk. We focus on substructures in the distribution of millimeter-sized and smaller solid particles produced by the vertical shear instability. We show that their characteristics are compatible with some of the shallow gaps detected in recent observations at sub-mm/mm wavelengths, and present predictions for future observations with better sensitivity and angular resolution with ALMA and a Next Generation Very Large Array.