Core and disk properties: from low- to high-mass star formation
Asmita Bhandare
Thursday December 6th, 14:40
Stars are formed by the gravitational collapse of dense, gaseous and dusty cores within magnetized molecular clouds. Understanding the complexity of the numerous physical processes involved in the very early stages of star formation requires detailed thermodynamical modeling in terms of radiation transport and phase transitions. For this we use a realistic gas equation of state via a density and temperature-dependent adiabatic index and mean molecular weight to model the phase transitions. We perform molecular core collapse simulations including the stages of first and second hydrostatic core formation in spherical symmetry using a gray treatment of radiative transfer coupled with hydrodynamics as detailed in Bhandare et al. 2018. We investigate the properties of Larson’s first and second cores and expand these collapse studies, for the first time to span a wide range of initial cloud masses from 0.5 Msun to 100 Msun. Thereby, we reveal a strong dependence of a variety of first core properties on the initial cloud mass. We find that the first core radius and mass increase from the low-mass to the intermediate-mass regime and decrease from the intermediate-mass to the high-mass regime. Most importantly, the lifetime of first cores strongly decreases towards the intermediate- and high-mass regime. Here, we demonstrate that low-mass protostars evolve through two distinct stages of formation of the first and second hydrostatic cores. In contrast, in the high-mass star formation regime, the collapsing cloud cores rapidly evolve through the first collapse phase and essentially immediately form Larson’s second cores. Furthermore, based on our new 2D radiation-hydrodynamics simulations, I will discuss the impact of different cloud properties on the formation of early disks around these objects.