Massive star formation remains one of the most challenging problems in astrophysics. The wide variety of physical processes involved, in particular the protostellar radiative feedback, increase the complexity of massive star formation in comparison with its low-mass counterpart.
We aim to study the details of mass accretion and ejection in the vicinity of massive star-forming cores using high-resolution (5 AU) numerical simulations. We use state-of-the-art three-dimensional adaptive-mesh-refinement models of massive dense core collapse, which integrate the equations of (resistive) grey radiation magnetohydrodynamics and include sink particle evolution. For the first time, we include both protostellar radiative feedback via pre-main-sequence evolutionary tracks and magnetic ambipolar diffusion. We investigate the mechanisms at the origin of outflows and the properties of the protostellar disc depending on the physics included: hydrodynamics, ideal magnetohydrodynamics, or ambipolar diffusion.
We find that magnetic processes dominate the early evolution of massive protostellar systems (up to 20 solar masses) and shape the accretion and ejection as well as the disc formation (Commerçon+22). Magneto-centrifugal processes are the main driver of the outflow. Then, the disc properties heavily depend on the physics included. In particular, the disc formed in the ideal and resistive runs show opposite properties in terms of plasma beta, and of magnetic field topology. The disc formed in the resistive runs is dominated by the thermal pressure and essentially has a vertical magnetic field in the inner regions (R < 100?200 AU).
To build upon these results, we then present simulations of more realistic environmental conditions including turbulence, and better numerical treatment of the star irradiation (Mignon-Risse+20). We identify the magnetic or radiative origin of massive protostellar outflows and compare their properties with observational constraints (Mignon-Risse+21b). With initial turbulence, we investigate the regulating mechanism of disk formation and the dependence of stellar multiplicity on the environment (Mignon-Risse+21a).