We examined the probability of planetesimal formation through dust direct growth. Recent results of our numerical simulation of aggregate collisions showed that collisions of icy aggregates result in coalescence rather than disruption as long as the collision velocity is less than several tens m/sec. Our numerical results also showed that dust aggregates are not compressed much at their collisions, which indicates that aggregates have an extremely low density in the course of their growth. By using this aggregate model, we find that the growth time of dust is much shoter than the time scale of dust infall due to gas drag in a wide region of the standard nebula model if dust settling increases the dust density by one order of magnitude. These our results support the direct growth model of planetesimal formation.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007