A New Mechanism of Dust Destruction by Massive Stars, Supernovae, and Kilonovae: Rotational Disruption by Radiative Torques
Massive stars, supernovae, and kilonovae are among the most luminous radiation sources in the universe. The powerful radiation from these sources is expected to have significant effects on the physical and chemical properties of surrounding environments. In this paper, we present a new, efficient destruction mechanism of large dust grains in strong radiation fields due to extremely fast rotation by radiative torques, which is termed RAdiative Torque Disruption (RATD) mechanism. We show that the RATD mechanism can destroy large grains located within a distance of $2$ pc from a massive star and supernova, and within 0.1 pc from a kilonova explosion, resulting in the enhancement of very small (size $a<0.01\mu$ m) and small dust grains. We find that the RATD mechanism can successfully explain several puzzles in dust astrophysics, including (i) the anomalous dust extinction towards SNe Ia, (ii) NIR-MIR emission excess from young massive star clusters, (iii) and Small Magellanic Cloud (SMC)-like extinction curves with a steep far-UV rise in starburst and high redshift galaxies. The enhancement of small grains by RATD also results in the decrease of the escape fraction of Ly$\alpha$ photons from \ion{H}{2} regions surrounding young massive star clusters. If interstellar grains are porous/aggregate, the RATD mechanism can also successfully explain the well-known lack of grains larger than $\sim 0.25\mu m$ in the diffuse interstellar medium of our galaxy. Modeling of dust evolution, dust emission, and polarization from intense radiation environments should account for the role of dust destruction by the RATD mechanism.