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Impact of Radiation Pressure and Ionizing Radiation Feedback in a Turbulent, Magnetized, Self-Gravitating, Massive Core-Collapse

expand: Figure 1
Figure 1: Collapse of a subvirial, 1000 M cloud with a radius of 1 pc and a linear magnetic field of 100 μG. Molecular Hydrogen is colored in orange and atomic Hydrogen in blue. A HII region (ionized Hydrogen colored in red) is formed at the center.

Birka Zimmermann

One of the largest unresolved problems in modern star formation is that of the formation of massive stars. Lower mass stars can primarily be explained due to the interplay of gravity, turbulence and thermal pressure leading to quasi-Jeans mass fragmentation; however, additional support against gravity is necessary for the formation of higher mass stars. This is thought to come primarily from magnetic fields and radiative feedback. High mass stars are also thought to evolve faster and start nuclear burning before the mass accretion process is finished, thus feedback and accretion happen at the same time.

We perform simulations with the magneto-hydrodynamic code FLASH which we have expanded to treat complex physical processes, including thermal and ionizing radiative feedback, essential to model high-mass star formation.

One of our simulations is shown in Fig. 1, where we present the collapse of a subvirial, 1000 M core with an initial radius of 1 pc and a linear magnetic field of 100 μG. Molecular Hydrogen is colored in orange, atomic Hydrogen in blue and ionized Hydrogen in red. During the collapse a sheet-like structure perpendicular to the magnetic field is formed. In the swept up material dense cores of around 10 M are launched. After 0.7 tff outflows along the magnetic field lines are ejected and after 0.9 tff a HII region in the center appears.