In He & Ricotti 2023, we investigate the formation and collapse of prestellar cores at ~10 AU resolution in a set of radiation-magneto-hydrodynamic simulations of giant molecular clouds. We adopt, for the first time to our best knowledge, realistic initial/boundary conditions by zooming-in onto individual massive prestellar cores within the GMC. We identify two primary fragmentation modes: quasi-spherical and filamentary. In both modes the fragments eventually become embedded in a quasi-steady accretion disk or toroid with radii ∼ 500 − 5000 AU. Our simulations reveal that each core converts nearly 100 percent of the gas mass into a few massive stars forming near the disk center. The most massive cores, exceeding tens of solar masses, forms a cluster through competitive accretion, while smaller cores tend to align with the turbulent core model.
In a subsequent work He & Ricotti 2024, we explore how do large Keplerian disks form in magnetically critical or near-critical cores. We discover that the magnetic field topology within these cores is highly turbulent and incoherent, which diminishes the effect of magnetic braking by roughly an order of magnitude. This substantial turbulence, driven by the non-axisymmetric gravitational collapse of the gas, primarily supports the vertical structure of the disks.