Experiments on the Photophoretic Motion of Chondrules and Dust Aggregates - Indications for the Transport of Matter in Protoplanetary Disks

TL;DR

This study experimentally investigates the photophoretic motion of sub-mm to mm-sized particles in microgravity, demonstrating its potential role in transporting matter outward in protoplanetary disks.

Contribution

First experimental analysis of photophoretic motion of mm-sized particles, validating theoretical models and exploring its efficiency in early Solar System transport processes.

Findings

Photophoretic forces align with theoretical predictions for spherical particles.

Force strength varies from low to strong depending on particle composition.

Photophoresis could effectively transport solid particles outward in protoplanetary disks.

Abstract

In a set of 16 drop tower experiments the motion of sub-mm to mm-sized particles under microgravity was observed. Illumination by a halogen lamp induced acceleration of the particles due to photophoresis. Photophoresis on dust-free chondrules, on chondrules, glass spheres and metal spheres covered with SiC dust and on pure SiC dust aggregates was studied. This is the first time that photophoretic motion of mm-sized particles has been studied experimentally. The absolute values for the photophoretic force are consistent with theoretical expectations for spherical particles. The strength of the photophoretic force varies for chondrules, dust covered particles and pure dust from low to strong, respectively. The measurements support the idea that photophoresis in the early Solar System can be efficient to transport solid particles outward.