Mechanical Torque Disruption of Dust Grains Induced by Supernova Shock Waves

Abstract: The feedback from massive stars drives the evolution of interstellar dust grains by altering their physical properties via a number of radiative and mechanical processes. Through these interactions, interstellar grains can achieve high rotational velocities due to unbalanced torques, potentially leading to their disruption. Mechanical torque disruption occurs when gas-grain collisions, induced by the passage of shocks, spin grains to critical rotational velocities. This study aims to investigate the effects of stochastic mechanical torque disruption on both pre-existent and supernova-condensed dust grains located within wind-blown bubbles. The impact of mechanical torque disruption on supernova-condensed dust and dust grains in wind-blown bubbles is investigated through post-processing of three-dimensional hydrodynamical simulation outputs. The associated timescale is then compared to those of kinetic sputtering and grain shattering. Before the supernova explosion, dust grain disruption timescales within wind-driven bubbles are on the order of millions of years due to the low-density environment. The timescales for mechanical torque disruption (METD) are longer than those for kinetic sputtering and comparable to those of grain shattering, primarily due the high grain drift velocities typical of these regions.