[P-PS07] Planetary Sciences

[PPS07-05] Analytical model of contact surface radius by collisions between pebbles and comparison with dust N-body simulations

*Misako Tatsuuma¹, Satoshi Okuzumi¹, Akimasa Kataoka², Hidekazu Tanaka³ (1.Tokyo Institute of Technology, 2.NAOJ, 3.Tohoku University)

Keywords:dust aggregates, pebbles, comets, planetesimals, compressive strength

To investigate the planet formation process, explorations of comets of the Solar System, which are thought to be survivors of planetesimals, have been actively conducted. Comets are thought to have been formed by the accumulation of millimeter-sized pebbles, which are compact aggregates of submicrometer-sized dust grains (e.g., Blum et al. 2022, for a review). When pebbles accumulate, contact surfaces are formed between the attached pebbles, and the contact surface radius determines the strength and thermal conductivity of pebble aggregates. Since the strength and thermal conductivity of comets have been determined by explorations, it is necessary to know the contact surface radius between the pebbles to determine the size and internal density of the pebbles that make up comets. However, the previous model of the contact surface radius between pebbles (Weidling et al. 2012) is incomplete because it does not describe the dependence on parameters such as the material and internal density of pebbles.

In this study, we tried to model the contact surface radius due to collisional adhesion between pebbles by using the compressive strength of dust aggregates. We obtained and formulated the compressive strength of dust aggregates by using adhesion N-body simulations that take into account the physics of the contact of dust grains. We succeeded in deriving the contact surface radius by balancing the kinetic energy of pebbles with the energy required to compress the collapsed volume due to the collisional adhesion of pebbles. We also performed collision simulations of pebbles by using adhesion N-body simulations and confirmed that our results are consistent with our analytical model. We will also discuss the potential applications of the modeled contact surface radius to the strength and thermal conductivity of pebble aggregates.