# Sticking Properties of Silicates in Planetesimal Formation Revisited

## TL;DR

This study measures the tensile strength of silicate dust aggregates with varying water content, supporting the idea that surface energy differences influence sticking properties relevant to planetesimal formation.

## Contribution

It provides empirical tensile strength data for dry and wet silicate dust aggregates, confirming the role of surface energy in dust sticking behavior during planetesimal formation.

## Key findings

- Dry samples are up to 10 times stronger than wet samples.
- A high surface energy value of 0.2 J/m^2 is appropriate for dry protoplanetary disk conditions.
- Results support the hypothesis that water layers affect dust aggregate strength.

## Abstract

In the past, laboratory experiments and theoretical calculations showed a mismatch in derived sticking properties of silicates in the context of planetesimal formation. It has been proposed by Kimura et al. (2015) that this mismatch is due to the value of the surface energy assumed, supposedly correlated to the presence or lack of water layers of different thickness on a grain's surface. We present tensile strength measurements of dust aggregates with different water content here. The results are in support of the suggestion by Kimura et al. (2015). Dry samples show increased strengths by a factor of up to 10 over wet samples. A high value of $\gamma = 0.2 J/m^2$ likely applies to the dry low pressure conditions of protoplanetary disks and should be used in the future.