2018/11/02 by Lars Mattsson, Akshay Bhatnagar, Frederick A. Gent +2 · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Atmospheric Ozone and Climate #Cluster analysis #Decoupling (probability) #Mechanics #Molecular cloud #Physics #Stars #Statistics #Turbulence #astro-ph.GA
paper · pdf · doi:10.1093/mnras/sty3369
19 pages, 16 figures. Submitted to MNRAS
arxiv created 2018/11/02 · openalex publication_date 2018/12/07 · arxiv updated 2018/12/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present high-resolution (10243) simulations of super-/hypersonic isothermal hydrodynamic turbulence inside an interstellar molecular cloud (resolving scales of typically 20–100 au), including a multidisperse population of dust grains, i.e. a range of grain sizes is considered. Due to inertia, large grains (typical radius |a \gtrsim 1.0 μ|m) will decouple from the gas flow, while small grains (|a\lesssim 0.1 μ|m) will tend to better trace the motions of the gas. We note that simulations with purely solenoidal forcing show somewhat more pronounced decoupling and less clustering compared to simulations with purely compressive forcing. Overall, small and large grains tend to cluster, while intermediate-size grains show essentially a random isotropic distribution. As a consequence of increased clustering, the grain–grain interaction rate is locally elevated; but since small and large grains are often not spatially correlated, it is unclear what effect this clustering would have on the coagulation rate. Due to spatial separation of dust and gas, a diffuse upper limit to the grain sizes obtained by condensational growth is also expected, since large (decoupled) grains are not necessarily located where the growth species in the molecular gas is.