Impact Angle Influence in High Velocity Dust Collisions during Planetesimal Formation

TL;DR

This study investigates how impact angle affects dust collision outcomes at high velocities, revealing that dust aggregates can grow at various angles, supporting planetesimal formation theories.

Contribution

It provides experimental data on impact angle effects in high-velocity dust collisions, highlighting conditions for dust growth relevant to planetesimal formation.

Findings

Growth occurs for projectiles smaller than 3 mm at 0° impact angle.

The threshold size for growth decreases to 1 mm at 45° impact angle.

Dust aggregates can grow at impact angles up to 45°, supporting sweep-up planetesimal formation.

Abstract

We have examined the influence of impact angle in collisions between small dust aggregates and larger dust targets through laboratory experiments. Targets consisted of \mum-sized quartz dust and had a porosity of about 67%; the projectiles, between 1 and 5 mm in diameter, were slightly more compact (64% porosity). The collision velocity was centered at 20 m/s and impact angles range from 0{\deg} to 45{\deg}. At a given impact angle, the target gained mass for projectiles smaller than a threshold size, which decreases with increasing angle from about 3 mm to 1 mm. The fact that growth is possible up to the largest angles studied supports the idea of planetesimal formation by sweep-up of small dust aggregates.