Stokes trapping and planet formation

TL;DR

The paper introduces 'Stokes trapping', a turbulence-induced barrier limiting dust aggregate growth in planet formation, and proposes a new theory to overcome this obstacle without relying on small cluster growth.

Contribution

It presents the concept of Stokes trapping as a new mechanism limiting dust growth and introduces a novel theory bypassing the growth of small dust clusters.

Findings

Stokes trapping constrains dust aggregate growth at Stokes number near unity.

Existing mechanisms are insufficient to overcome the growth barrier.

A new theory is proposed that does not depend on small cluster growth.

Abstract

It is believed that planets are formed by aggregation of dust particles suspended in the turbulent gas forming accretion disks around developing stars. We describe a mechanism, termed 'Stokes trapping', by which turbulence limits the growth of aggregates of dust particles, so that their Stokes number (defined as the ratio of the damping time of the particles to the Kolmogorov dissipation timescale) remains close to unity. We discuss possible mechanisms for avoiding this barrier to further growth. None of these is found to be satisfactory and we introduce a new theory which does not involve the growth of small clusters of dust grains.