Contributed Talk - Splinter Computation

Thursday, 24 September 2020, 11:43   (virtual room B)

Zooming in on star and disk formation

A. Bhandare, R. Kuiper, Th. Henning, C. Fendt, M. Flock, and G.-D. Marleau
Max Planck Institute for Astronomy, University of Tuebingen, University of Bern

Magnetized, cold, dense molecular cloud cores provide the birth environment for stars and disks. The multi-scale scenario of low-mass star formation occurs via the formation of two quasi-hydrostatic cores. In this talk I will discuss results from numerical simulations used to probe the gravitational collapse process that involves the transition of an isolated molecular cloud core to a hydrostatic core with a surrounding disk. We use the PLUTO code to perform radiation (magneto-)hydrodynamic simulations using one- and two- dimensional (2D) grids. Additionally, we use for the gas equation of state density- and temperature-dependent thermodynamic quantities to account for dissociation, ionization, and molecular vibrations and rotations. Using spherically symmetric simulations we survey a wide range of initial low- to high-mass (0.5 - 100 Msun) molecular cloud cores, yielding the largest parameter scan so far. The results highlight that in the high-mass regime first hydrostatic cores do not have time to evolve because of the large accretion rates. We perform 2D collapse simulations with an unprecedented resolution to model the evolution of the second hydrostatic core. For the first time, these studies demonstrate the onset of convection within the second core for the collapse cases of non-rotating molecular cloud cores in the low-mass regime. This supports the interesting possibility that dynamo-driven magnetic fields may be generated during the very early phases of low-mass star formation. Furthermore, I will discuss the impact of different cloud properties on the formation of protostellar disks and the launching of magnetically driven outflows during the early stages of star formation. These models will serve as the foundation for follow-up studies that link theoretical insights with observational signatures.