| Abstract |
Impact processes in our Solar system play a crucial role in formationand evolution of the planets. In particular, formation process ofplanetesimals through collisions of dust aggregates still remainsunclear. We perform numerical simulations of aggregate collisions toexamine the evolution of dust aggregates in protoplanetary disks. As aresult, we have found that aggregates are not compressed well by theirmutual collisions and the fractal dimension of the compressed aggregatesis at most ~ 2.5. The aggregates composed of ice particles are feasibleto grow even if the impact velocities are as high as a few tens of m/s.These numerical results suggest that very fluffy planetesimals can beformed in protoplanetary disks by direct collisional growth of dust.There are still many problems remaining, such as the feasibility ofcollisional growth of silicate aggregates. We believe that theseproblems are resolved through our collision simulations and the growthof dust aggregates are fully understood in the future. |
