The HADES simulations aim to resolve the accretion from massive disks onto embedded protostars from the disk to the protostellar surface at maximal resolutions of order 10-5 - 10-4 AU.
Description: Evolution of the accretion flow from the inner 0.2 AU onto the protostar surface. The left side shows the density while the right shows the temperature.
How protostars accrete their mass is still a highly debated topic. The HADES simulations focus on the main accretion phase when accretion rates exceed 10-9 M☉/yr and raise to over 10-5 M☉/yr. These simulations will focus on exploring in unprecedented detail the physical mechanisms by which gas flows from the disk onto the protostar and how this gas can be expelled from the system through winds. HADES is the first such simulation of accretion at these phases resolving the flow from the disks onto the protostellar surface. We use the public magneto-hydrodynamic code PLUTO.
The dynamics of the gas within the inner disks vary vastly between sub- and super-Alfvenic, with the magnetic field being dominant inside the Alfven surface and a largely super-Alfvenic and turbulent inner disk. Resolving the dynamics within the inner disk and the flow onto the protostar surface requires capturing the large scale flows to shocks on mAU scales. HADES aims to resolve the accretion flows with a maximal resolution of 20 μAU (3000 km, or 0.5 R🜨) while keeping mAU resolution throughout the disk. We accomplish this through the use a logarithmic grid so the domain is well resolved from the protostar surface to 1 AU. The simulations will constrain the production sites of high-energy radiation and resolve important physical mechanisms such as magnetic reconnection.
Description: A zoom-in of the grid structure at the boundary at the protostar surface for a simulation with a maximal resolution of 4⨯10-4; AU. Background image shows the gas density at t = 6 days.
We acknowledge support from the Chalmers Centre for Computational Science and Engineering (C3SE), Swedish National Infrastructure for Computing (SNIC) and the PDC Center for High Performance Computing which runs the Dardel system. These simulations were run on the Dardel cluster through proposal SNIC 2022/5-654. BG acknowledges support from the Chalmers Initative on Cosmic Origins (CICO) at Chalmers University of Technology in Gothenburg, SE.
All in good time...