Fine-grained rims as probes of dusty protoplanetary environments

During planet formation within circumstellar disks, dust coagulation is a critical step in the process, particularly in the growth of solids at the sub-millimeter to meter scales. Dust coatings, known as fine-grained rims (FGRs), have been observed on these bodies and are hypothesized to form from the accretion of nebular dust onto chondrules. Thus, FGRs are a key element in the formation of chondrite parent bodies, providing insight into their collisional history. Slow collision speeds are generally assumed necessary in order to lead to the formation of chondrule rims. As such, less experimental or theoretical attention has been given to the role that higher speed collisions or charged dust might play in the formation process. At least as important is the data such rims might provide on both the formation process as well as the surrounding nebula. This regime is important since Liffman (2019) recently suggested that higher-speed collisions might produce 'coatings' on chondrule surfaces as a result of the fragmentation of impinging micron-sized grains. We report on recent experimental results collected within a dusty environment for an operating parameter space designed to better establish the FGR formation process for particle / chondrule collisions.