Effects of Dust Coagulation on Streaming Instability

TL;DR

This study combines dust coagulation with streaming instability modeling in stratified protoplanetary disks, showing coagulation promotes dust growth and enables SI triggering, expanding previous parameter boundaries.

Contribution

First numerical simulation integrating dust coagulation with streaming instability in a vertically stratified disk, revealing coagulation's role in SI initiation.

Findings

Dust coagulation promotes dust size growth.

SI can be triggered from small initial dust sizes.

Coagulation broadens SI parameter space.

Abstract

Streaming Instability (SI) in dust has long been thought to be a promising process in triggering planetesimal formation in the protoplanetary disks (PPDs). In this study, we present the first numerical investigation that models the SI in the vertically stratified disk together with the dust coagulation process. Our simulations reveal that, even with the initial small dust sizes, because dust coagulation promotes dust size growth, SI can eventually still be triggered. As such, the dust coagulation process broadens the parameter boundaries obtained from the previous SI studies using single dust species. We describe the various stages of dust dynamics along with their size evolution, and explore the impact of different dust fragmentation velocities. Implications of these results for realistic PPDs are also discussed.