Dust evolution by chemisputtering during protostellar formation

¹ Centre de Recherche en Astrophysique de Lyon, ENS Lyon, UMR 5574 CNRS, Université de Lyon, 46 allée d’Italie, Lyon, France
² Laboratoire de Géologie de Lyon, ENS Lyon, UMR 5276 CNRS, Université de Lyon, 46 Allée d’Italie, Lyon, France

^★ Corresponding author; antonin.borderies@yahoo.fr

Received: 13 September 2024
Accepted: 13 January 2025

Abstract

Context. Dust grains play a crucial role in the modeling of protostellar formation, particularly through their opacity and interaction with the magnetic field. The destruction of dust grains in numerical simulations is currently modeled primarily by temperaturedependent functions. However, a dynamical approach could be necessary to accurately model the vaporization of dust grains.

Aims. We focused on modeling the evolution of dust grains during star formation, specifically on the vaporization of the grains by chemisputtering. We also investigated the evolution of non-ideal magnetohydrodynamic resistivities and the Planck and Rosseland mean opacities influenced by the grain evolution.

Methods. We modeled the evolution of the dust by considering spherical grains at thermal equilibrium with the gas phase, composed only of one kind of material for each grain. We then took into account the exchange processes that can occur between the grains and the gas phase and that make the grain size evolve. We considered three materials for the grains: carbon, silicate, and aluminum oxide. Given a temporal evolution in temperature and density of the gas phase, we computed the evolution of a dust grain distribution. This evolution was then used to compute the non-ideal magnetohydrodynamic resistivities and the Planck and Rosseland mean opacities.

Results. We observed a significant dependence of the sublimation temperature of the carbon grains on the dynamical evolution of the gas phase. The application of our method to trajectories where the temperature and density of the gas decrease after the sublimation of a portion of the grain distribution highlights the limitations of current vaporization prescriptions in simulations.

Conclusions. The dynamical approach leads to more accurate results for the carbon grain quantity when the temperature and density of the gas evolve quickly. The dynamical approach application to collapse and disk evolution is then foreseen with its integration into hydrodynamic simulations.