3D radiative hydrodynamic simulations of protostellar collapse with H-C-O dynamical chemistry

Abstract

Combining the co-evolving chemistry, hydrodynamics and radiative transfer is an important step for star formation studies. It allows both a better link to observations and a self-consistent monitoring of the magnetic dissipation in the collapsing core. Our aim is to follow a chemo-dynamical evolution of collapsing dense cores with a reduced gas-grain chemical network. We present the results of radiative hydrodynamic (RHD) simulations of 1 M$_\odot$ isolated dense core collapse. The physical setup includes RHD and dynamical evolution of a chemical network. To perform those simulations, we merged the multi-dimensional adaptive-mesh-refinement code RAMSES and the thermo-chemistry Paris-Durham shock code. We simulate the formation of the first hydro-static core (FHSC) and the co-evolution of 56 species describing mainly H-C-O chemistry. Accurate benchmarking is performed, testing the reduced chemical network against a well-establiched complex network. We show that by using a compact set of reactions, one can match closely the CO abundances with results of a much more complex network. Our main results are: (a) We find that gas-grain chemistry post-processing can lead to one order of magnitude lower CO gas-phase abundances compared to the dynamical chemistry, with strongest effect during the isothermal phase of collapse. (b) The free-fall time has little effect on the chemical abundances for our choice of the parameters. (c) Dynamical chemical evolution is required to describe the CO gas phase abundance as well as the CO ice formation for the mean grain size larger then 1$\mu{}$m. (d) Furthermore, dust mean size and size distribution have a strong effect on chemical abundances and hence on the ionization degree and magnetic dissipation. We conclude that dust grain growth in the collapse simulations can be as important as coupling the collapse with chemistry.