Acceleration and clustering of cosmic dust in a gravoturbulent gas -- I. Numerical simulation of the nearly Jeans-unstable case

Abstract

We investigate the dynamics of interstellar dust particles in moderately high resolution ($512^3$ grid points) simulations of forced compressible transonic turbulence including self-gravity of the gas. Turbulence is induced by stochastic compressive forcing which is delta-correlated in time. By considering the nearly Jeans-unstable case, where the scaling of the simulation is such that a statistical steady state without any irreversible collapses is obtained, we obtain a randomly varying potential, acting as a second stochastic forcing. We show that, in this setting, low-inertia grains follow the gas flow and cluster in much the same way as in a case of statistical steady-state turbulence without self-gravity. Large, high-inertia grains, however, are accelerated to much higher mean velocities in the presence of self-gravity. Grains of intermediate size also show an increased degree of clustering. We conclude that self-gravity effects can play an important role for aggregation/coagulation of dust even in a turbulent system which is not Jeans-unstable. In particular, the collision rate of large grains in the interstellar medium can be much higher than predicted by previous work.

17 pages, 11 figures, accepted for publication MNRAS. Reference list corrected

References in corpus (10)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Heavy particle concentration in turbulence at dissipative and inertial scales
• The Pencil Code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained
• Multifractal concentrations of inertial particles in smooth random flows
• Is the dust-to-gas ratio constant in molecular clouds?
• The Herschel exploitation of local galaxy Andromeda (HELGA) V: Strengthening the case for substantial interstellar grain growth
• Dust-depletion sequences in damped Ly-α absorbers II. The composition of cosmic dust, from low-metallicity systems to the Galaxy
• Small-scale clustering of nano-dust grains in supersonic turbulence
• Coagulation of inertial particles in supersonic turbulence
• Kinetics and clustering of dust particles in supersonic turbulence with self-gravity

Cited by in corpus (1)

• Dust dynamics in RAMSES -- I. Methods and turbulent acceleration