Zooming in on star and disk formation.

Asmita Bhandare, Max Planck Institute for Astronomy Heidelberg - 13.01.20

Abstract:

Magnetized, cold, dense molecular cloud cores provide the birth environment for stars and disks. This work is aimed at understanding the multi-scale scenario of star formation, which occurs via the formation of two quasi-hydrostatic Larson cores. We perform spherically symmetric, isolated, molecular cloud collapse simulations using the radiation (magneto)hydrodynamic code PLUTO as a tool. These one-dimensional studies, spanning 7 orders of magnitude in spatial scales, account for the phase transitions by using a realistic gas equation of state via a density- and temperature-dependent adiabatic index and mean molecular weight. For the first time, a large parameter scan across initial low- to high-mass (0.5 Msun – 100 Msun) molecular cloud cores is surveyed. In this talk, I will highlight the dependence of the first and second hydrostatic core properties on the initial cloud properties. The results indicate that in the high-mass regime, first hydrostatic cores do not have time to evolve because of the large accretion rates. Following these results, we have investigated the evolution of the second hydrostatic core using two-dimensional radiation hydrodynamic collapse simulations with a resolution that has not been achieved before. These studies demonstrate, for the first time, 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 an interesting possibility that dynamo-driven magnetic fields may be generated during the very early phases of low-mass star formation. Additionally, I will also discuss the impact of different cloud properties on the formation and evolution of circumstellar disks, formed due to the conservation of angular momentum.