[P-PS06] Planetary Sciences

[PPS06-03] Collisional Growth and Fragmentation of Dust Aggregates with Low Mass Ratios

*Yukihiko Hasegawa¹, Takeru Suzuki¹, Hidekazu Tanaka², Hiroshi Kobayashi³, Koji Wada⁴ (1.The University of Tokyo, 2.Tohoku University, 3.Nagoya University, 4.Chiba Institute of Technology)

Keywords:Numerical simulation, Planet formation, Protoplanetary disk

We investigated fundamental processes of collisional sticking and fragmentation of dust aggregates composed of submicron-sized icy dust monomers. We carried out N-body simulations of dust monomers. We examined the condition for collisional growth of two colliding dust aggregates in a wide range of the mass ratio, 1-64. We found that the mass transfer from a larger dust aggregate (called a target) to a smaller one (called a projectile) is a dominant process in collisions with a mass ratio of 2-30 and the impact velocity of about 30-170 m per s. As a result, the critical velocity for collisional fragmentation of the target is considerably reduced for such unequal-mass collisions; the critical fragmentation velocity of collisions with a mass ratio of 3 is about half of that obtained from equal-mass collisions. The impact velocity is generally higher for collisions between dust aggregates with higher mass ratios because of the difference between the radial drift velocities in the typical condition of protoplanetary disks. Therefore, the reduced critical fragmentation velocity for unequal-mass collisions would delay growth of dust grains in the inner region of protoplanetary disks.