Presentation #410.03 in the session Dynamical Interactions in the Kuiper Belt (iPosters).
During the early stages of the Solar System, nebular gas and sub-mm dust evolved into pebbles, which grew to form planetesimals, which in turn accreted to form proto-planets and eventually the planets that we observe in our current solar system. When pebbles reach cm-sizes, growth as a result of pairwise collisions is no longer effective due to growth barriers. On the other hand, growth to planetesimal sizes (1 km – 100 km) can occur via the gravitational collapse of pebble clouds aggregated by interactions between the solid pebbles and the gas disk, as in the streaming instability. Here, we use the astrophysical N-body integrator PKDGRAV with its soft-sphere discrete element method, which models contact forces between particles, to conduct numerical experiments to understand how properties of the collapsing pebble cloud affect the resulting accreted planetesimal system. We are exploring the consequences of oblate and prolate clouds in contrast and comparison to published models that use strictly idealized spherical clouds. In addition, we are varying the initial random velocities to consider the influence of turbulent mixing in the protoplanetary disk. In all of these scenarios, we are analyzing how these independent variables affect the efficiency of planetesimal accretion, including the final mass of formed planetesimals, the number of accreted planetesimals, and the multiplicity of planetesimal systems (binary, ternary, etc.). Specifically, we are interested in the properties of the binary system because comparing these to observed cold classical Kuiper Belt objects acts as direct verification of our numerical models, since this dynamical subregion has remained untouched since the era of planetesimal formation.