The aeolian-erosion barrier for the growth of metre-size objects in protoplanetary-discs

TL;DR

This paper demonstrates that aeolian-erosion in protoplanetary discs can significantly hinder the growth of small planetary objects by eroding them down to tens of centimeters, posing challenges to planet formation theories.

Contribution

It introduces the concept that aeolian-erosion acts as a barrier in protoplanetary discs, affecting early planetesimal growth and highlighting its dual role in both hindering and potentially aiding planet formation.

Findings

Aeolian-erosion can erode small bodies down to tens of centimeters.

Erosion raises difficulties for the metre-size barrier in planet formation.

Decimetre-sized cobbles may enhance growth of larger planetesimals via pebble-accretion.

Abstract

Aeolian-erosion is a destructive process which can erode small-size planetary objects through their interaction with a gaseous environment. Aeolian-erosion operates in a wide range of environments and under various conditions. Aeolian-erosion has been extensively explored in the context of geophysics in terrestrial planets. Here we show that aeolian-erosion of cobbles, boulders and small planetesimals in protoplanetary-discs can constitute a significant barrier for the early stages of planet formation. We use analytic calculations to show that under the conditions prevailing in protoplanetary-discs small bodies ($10-10^4 \rm{m}$) are highly susceptible to gas-drag aeolian-erosion. At this size-range aeolian-erosion can efficiently erode the planetesimals down to tens-cm size and quench any further growth of such small bodies. It thereby raises potential difficulties for channels suggested to alleviate the metre-size barrier. Nevertheless, the population of $\sim$decimetre-size cobbles resulting from aeolian-erosion might boost the growth of larger (>km size) planetesimals and planetary embryos through increasing the efficiency of pebble-accretion, once/if such large planetesimals and planetary embryos exist in the disc.