Simulating dust monomer collisions: The JKR theory revisited
speaker: Yuki Yoshida
Abstract:
Planet formation proceeds in protoplanetary disks, which are composed of dust and gas. Dust is the material of planetary bodies, and it is considered that the minimum building block of the dust is dust monomers whose size is sub-micrometer. Dust monomers grow by collisional sticking and form dust aggregates. The JKR theory is widely adopted in the numerical simulation of collisions of dust monomers/aggregates. The JKR theory describes the interaction of two spherical bodies of elastic solids. The properties of dust aggregates are important in determining the distribution of the dust and its growth rate, which are related to the planetesimal formation. Laboratory experiments and numerical simulation have been carried out to reveal the growth of dust monomers and aggregates. However, the results of the experiments and the simulations based on the JKR theory are still inconsistent. For example, the threshold velocity for sticking in the experiment is larger than that with the JKR theory (e.g., Poppe et al. 2020; Gundlach and Blum 2015). Krijt et al. (2013) considered that the energy dissipation due to the viscoelasticity is important, which is not included in the JKR theory. Tanaka et al. (2015) performed the molecular dynamics (MD) simulation of the monomer collisions, and found energy dissipation during monomer collisions, which is not included in the JKR theory. However, Tanaka et al. (2015) considered only the perfect lattice model, and didn’t systematically investigate the monomer collision.
We are preparing a systematic survey of monomer collisions by MD simulations to understand the more realistic monomer interactions. In this talk, we introduce our purpose of this study, and show the results of test simulations following Tanaka et al. (2015).