The growth of macroscopic bodies in protoplanetary disks: experimental evidences
Seminar Room 1, Newton Institute
AbstractI will review the various laboratory and microgravity experiments on low-velocity dust-aggregate collisions and will present a systematic description of the possible outcomes of such collisions. Depending on the aggregate masses, mass ratios, porosities, and collision velocities, we can distinguish between four types of sticking, two types of bouncing, and three types of fragmentation. Careful interpolation between and extrapolation of the experimental results into yet uncovered parameter space allows us to describe the protoplanetary dust growth from initially micrometer-sized grains in a self-consistent way, using a recently-developed Monte-Carlo method. The results of the first simulations show that bouncing is the dominant process after a rapid initial growth stage, which limits the maximum aggregate sizes achievable in protoplanetary disks to 100 ?m - 1 cm, depending on the disk model used. The simulations also reveal the growth path of the dust aggregates through the multi-parameter space, which is being used to define new laboratory experiments. With this bi-directional feeback between experiments and modeling, we are able to refine the results of protoplanetary dust growth modeling and to achieve solid data for the maximum size, the size distribution, and the porosities of the aggregates.
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