Growth of cosmic dust aggregates and reexamination of particle interaction models

Dust growth is the first step of planet formation in protoplanetary disks. Dust growth also influences the temperature of protoplanetary disks. However, we still have a large uncertainty in the dust growth process. This uncertainty mainly comes from unknown factors in dust internal structure and collisional outcomes. The dust structure and the collisional outcome would be closely related with each other. In recent years, many theoretical studies on aggregate collisions and growth have been done. In the present paper, we introduce remarkable results in these theoretical studies, mainly focusing on numerical simulations of dust collisions by our group. In the numerical simulations of dust collisions, we adopt the interaction model between constituent particles of dust aggregates. We have started the rexamination of the particle interaction model, by performing molecular dymnamics simulation of particle collisions. We also report the preliminary results of our molecular dynamics simulations.