PI: Cathie Clarke

Highlight (dp047): Simulation of the outcome of a flyby of a protoplanetary disc by a passing star, using the PHANTOM SPH code in two fluid (dust+ gas) mode (Prasad et al 2025; MNRAS 543,1798). The Image below is a post-encounter snapshot showing the dust to gas ratio and demonstrates that the flyby induces a set of ring-like over-densities in the dust component. Through tracing the histories of dust particles contained in these over-densities, we demonstrate that the magnitude of the enhancement in the dust to gas ratio, together with the duration over which dust particles remain in such over-densities, imply conditions that are potentially favourable for inducing dust collapse through the action of the streaming instability. This work therefore points to a possible role of external perturbations in triggering the collapse of solid material in protoplanetary discs, a necessary first step for the creation of rocky planets and the cores of giant planets. These calculations were performed on DIAL (University of Leicester).