Modelling dust processing and the evolution of grain sizes in the ISM using the method of moments

TL;DR

This paper introduces a computationally efficient statistical model using the method of moments to simulate dust processing and grain size evolution in the interstellar medium, accounting for various dust formation and destruction mechanisms.

Contribution

It presents a novel application of the method of moments for modeling dust evolution, enabling integration with complex gas dynamics simulations.

Findings

The model captures dust growth, destruction, and coagulation processes.

It demonstrates computational efficiency suitable for large-scale simulations.

A toy model of the solar neighborhood illustrates the approach.

Abstract

Interstellar dust grains do not have a single well-defined origin. Stars are demonstrably dust producers, but also efficient destroyers of cosmic dust. Dust destruction in the ISM is believed to be the result of SN shocks hitting the ambient ISM gas (and dust) and lead to an increased rate of ion sputtering, which reduces the dust mass. Grains located in cold molecular clouds can on the other hand grow by condensation, thus providing a replenishment mechanism or even a dominant channel of dust formation. In dense environments grains may coagulate and form large composite grains and aggregates and if grains collide with large enough energies they may be shattered, forming a range of smaller debris grains. The present paper presents a statistical modelling approach using the method of moments, which is computationally very inexpensive and may therefore be an attractive option when combining dust processing with, e.g., detailed simulations of interstellar gas dynamics. A solar-neighbourhood-like toy model of interstellar dust evolution is presented as an example.