Protostellar collapse simulations in spherical geometry with dust coagulation and fragmentation

Abstract

We model the coagulation and fragmentation of dust grains during the protostellar collapse with our newly developed shark code. It solves the gas-dust hydrodynamics in a spherical geometry and the coagulation/fragmentation equation. It also computes the ionization state of the cloud and the Ohmic, ambipolar and Hall resistivities. We find that the dust size distribution evolves significantly during the collapse, large grain formation being controlled by the turbulent differential velocity. When turbulence is included, only ambipolar diffusion remains efficient at removing the small grains from the distribution, brownian motion is only efficient as a standalone process. The macroscopic gas-dust drift is negligible for grain growth and only dynamically significant near the first Larson core. At high density, we find that the coagulated distribution is unaffected by the initial choice of dust distribution. Strong magnetic fields are found to enhance the small grains depletion, causing an important increase of the ambipolar diffusion. This hints that the magnetic field strength could be regulated by the small grain population during the protostellar collapse. Fragmentation could be effective for bare silicates, but its modeling relies on the choice of ill-constrained parameters. It is also found to be negligible for icy grains. When fragmentation occurs, it strongly affects the magnetic resistivities profiles. Dust coagulation is a critical process that needs to be fully taken into account during the protostellar collapse. The onset and feedback of fragmentation remains uncertain and its modeling should be further investigated.

Accepted for publication in MNRAS

References in corpus (22)

• Theory of Star Formation
• Coagulation, fragmentation and radial motion of solid particles in protoplanetary disks
• Closed-form expressions for particle relative velocities induced by turbulence
• The evolution of amorphous hydrocarbons in the ISM: dust modelling from a new vantage point
• Dust size distributions in coagulation/fragmentation equilibrium: Numerical solutions and analytical fits
• Dust retention in protoplanetary disks
• Magnetically self-regulated formation of early protoplanetary discs
• Second Core Formation and High Speed Jets: Resistive MHD Nested Grid Simulations
• Low dust emissivities and radial variations in the envelopes of Class 0 protostars: a signature of early grain growth?
• "Ash-fall" induced by molecular outflow in protostar evolution
• Protostellar collapse: the conditions to form dust rich protoplanetary disks
• Protoplanetary disk birth in massive star forming clumps: the essential role of the magnetic field
• On the dynamics of dust during protostellar collapse
• Small dust grain dynamics on adaptive mesh-refinement grids. I. Methods
• Rapid Elimination of Small Dust Grains in Molecular Clouds
• Grain growth for astrophysics with Discontinuous Galerkin schemes
• Impact of the Hall effect in star formation : improving the angular momentum conservation
• Fragmentation with Discontinuous Galerkin schemes: Non-linear fragmentation
• Dust coagulation and fragmentation in a collapsing cloud core and their influence on non-ideal magnetohydrodynamic effects
• Impact of magneto-rotational instability on grain growth in protoplanetary disks: II. Increased grain collisional velocities
• Impact of dust size distribution including large dust grains on magnetic resistivity: an analytical approach
• Grain Growth During Protostellar Disk Formation

Cited by in corpus (6)

• Compaction during fragmentation and bouncing produces realistic dust grain porosities in protoplanetary discs
• Accuracy of ALMA estimates of young disk radii and masses. Predicted observations from numerical simulations
• Impact of turbulence intensity and fragmentation velocity on dust particle size evolution and non-ideal magnetohydrodynamics effects
• Dust evolution during the protostellar collapse: influence on the coupling between the neutral gas and the magnetic field
• Star-forming environments in smoothed particle magnetohydrodynamics simulations I: Clump extraction and properties
• Co-evolution of dust grains and protoplanetary disks II: structure and evolution of protoplanetary disks; an analytical approach