Self-induced dust traps: overcoming planet formation barriers

TL;DR

This paper introduces a robust self-induced dust trapping mechanism in protoplanetary discs, overcoming growth barriers and facilitating planetesimal formation through dust-gas interactions and large-scale pressure structures.

Contribution

It reveals a novel self-induced dust trap process driven by dust backreaction and gradients, promoting planet formation beyond previous limitations.

Findings

Dust traps form across various disc conditions.

Traps enable growth from pebbles to planetesimals.

Mechanism overcomes radial-drift and fragmentation barriers.

Abstract

Planet formation is thought to occur in discs around young stars by the aggregation of small dust grains into much larger objects. The growth from grains to pebbles and from planetesimals to planets is now fairly well understood. The intermediate stage has however been found to be hindered by the radial-drift and fragmentation barriers. We identify a powerful mechanism in which dust overcomes both barriers. Its key ingredients are i) backreaction from the dust onto the gas, ii) grain growth and fragmentation, and iii) large-scale gradients. The pile-up of growing and fragmenting grains modifies the gas structure on large scales and triggers the formation of pressure maxima, in which particles are trapped. We show that these self-induced dust traps are robust: they develop for a wide range of disc structures, fragmentation thresholds and initial dust-to-gas ratios. They are favored locations for pebbles to grow into planetesimals, thus opening new paths towards the formation of planets.