# A unique solution to overcome the barriers to planetesimal formation at low dust-to-gas ratio

## TL;DR

This paper demonstrates through numerical simulations that in weakly turbulent protoplanetary disks, solid grains can concentrate and their radial drift can be slowed or halted, enabling planetesimal formation at standard dust-to-gas ratios.

## Contribution

It introduces a novel simulation approach capturing full turbulence cascade, showing planetesimal formation is possible at canonical dust-to-gas ratios in weak turbulence conditions.

## Key findings

- Solid grains form dense clusters in weak turbulence
- Radial drift of grains can be slowed or stopped
- Planetesimal formation feasible at standard dust-to-gas ratio

## Abstract

In the incremental growth model, planetesimal formation constitutes the least understood step in the process of planetary formation. The two main difficulties in this regard are the collision/fragmentation and the drift barriers. Numerous solutions have been proposed to overcome these barriers, but often need a conjunction of processes to reach the conditions for planetesimal formation. We present numerical simulations, in which the protoplanetary disk turbulence is fully captured rather than modeled with a turbulent diffusion or turbulent viscosity parameter. When the turbulent cascade is taken into account, and in the case of weakly turbulent disks, not only can solid grains be highly concentrated in clusters, but their radial drift can also be slowed or even halted. These results open a unique path to planetesimal formation starting at disk canonical dust-to-gas ratio, namely Keplerian turbulence.