Numerical determination of the material properties of porous dust cakes

TL;DR

This paper calibrates a numerical model of dust aggregate dynamics to experimental data, enabling better understanding of mechanical properties crucial for planetesimal formation.

Contribution

It introduces a calibration of a numerical aggregate model using plastic deformation of surface asperities to match experimental sticking velocities.

Findings

The calibrated model accurately predicts compression strength.

The model reproduces the velocity of sound in aggregates.

It demonstrates capability to study small aggregate properties.

Abstract

The formation of planetesimals requires the growth of dust particles through collisions. Micron-sized particles must grow by many orders of magnitude in mass. In order to understand and model the processes during this growth, the mechanical properties, and the interaction cross sections of aggregates with surrounding gas must be well understood. Recent advances in experimental (laboratory) studies now provide the background for pushing numerical aggregate models onto a new level. We present the calibration of a previously tested model of aggregate dynamics. We use plastic deformation of surface asperities as the physical model to bring critical velocities for sticking into accordance with experimental results. The modified code is then used to compute compression strength and the velocity of sound in the aggregate at different densities. We compare these predictions with experimental results and conclude that the new code is capable of studying the properties of small aggregates.