Planetesimal gravitational collapse in a gaseous environment: Thermal and dynamic evolution

TL;DR

This study uses numerical simulations to explore the thermal and dynamic evolution of planetesimals during gravitational collapse in a gaseous environment, highlighting the gas's crucial role in heating and energy distribution.

Contribution

It provides new insights into the thermal evolution and energy distribution during planetesimal collapse, emphasizing the importance of gas in the process.

Findings

Temperatures up to 1600 K can be reached during collapse.

Gas significantly influences the thermal and dynamical evolution.

Energy from gravitational contraction is distributed among different components.

Abstract

Planetesimal formation models often invoke the gravitational collapse of pebble clouds to overcome various barriers to grain growth and propose processes to concentrate particles sufficiently to trigger this collapse. On the other hand, the geochemical approach for planet formation constrains the conditions for planetesimal formation and evolution by providing temperatures that should be reached to explain the final composition of planetesimals, the building blocks of planets. To elucidate the thermal evolution during gravitational collapse, we used numerical simulations of a self-gravitating cloud of particles and gas coupled with gas drag. Our goal is to determine how the gravitational energy relaxed during the contraction is distributed among the different energy components of the system, and how this constrains a thermal and dynamical planetesimal's history. We identify the conditions necessary to achieve a temperature increase of several hundred kelvins, and as much as 1600 K. Our results emphasise the key role of the gas during the collapse.