Collisions between granular micro-aggregates: conditions for dust agglomeration

BELÉN PLANES

Conferencia; Five years after HL Tau: a new era in planet formation; 2020

ESO

Collisions between dust aggregates are important in many astrophysical environments. In planetary formation it is crucial to understand how a system evolves through collisions, as it is currently unknown how dust aggregates grow to form planetesimals, and eventually, larger bodies like planets. We use complex numerical simulations in micro-scale to study how variations in impact velocity but also in porosity and in the mass difference between the projectile and the target affect the result of the collision. Our interest is to find the threshold values that separate agglomeration from fragmentation. We found that the impact velocity necessary to fracture the target varies with the porosity and the mass ratio between the aggregates, contrary to previous studies that assume it independent of these variables. From our results we conclude that dust growth due to collisional processes could be more feasible than in previous estimates.