Overcoming the Meter Barrier and The Formation of Systems with Tightly-packed Inner Planets (STIPs)

TL;DR

This paper proposes a solution to the meter barrier problem in planet formation, explaining how solids can grow rapidly in hot, dense disk regions, which may account for the observed Systems with Tightly-packed Inner Planets (STIPs).

Contribution

It introduces a novel mechanism where high partial pressures of rock vapor enable rapid solid growth despite high temperatures, addressing a key challenge in planet formation theory.

Findings

High partial pressures of rock vapor suppress solid evaporation.

Rapid growth of partially molten solids is facilitated in hot disk regions.

The mechanism explains the formation of STIPs observed by Kepler.

Abstract

We present a solution to the long outstanding meter barrier problem in planet formation theory. As solids spiral inward due to aerodynamic drag, they will enter disk regions that are characterized by high temperatures, densities, and pressures. High partial pressures of rock vapor can suppress solid evaporation, and promote collisions between partially molten solids, allowing rapid growth. This process should be ubiquitous in planet-forming disks, which may be evidenced by the abundant class of Systems with Tightly-packed Inner Planets (STIPs) discovered by the NASA Kepler mission.