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| EPoS Contribution |
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Influence of the Initial Conditions on Massive Star Formation
Philipp Girichidis Institut für theoretische Astrophysik, Heidelberg, Germany | |
| The influence of the initial conditions during the collapse of the gas cloud on the fragmentation, the local formation process and the evolution of mass accretion onto the protostellar cores is still unclear and can not be quantified, yet. Among the initial conditions, the interplay between the density distribution, the structure of turbulent motion, the rotation of the gas cloud and self-gravity are likely to have the first important impact, and trigger the fragmentation process long before other physical processes like radiation and the initiation of nuclear burning play a significant role. In order to shed light on the connection between these initial properties of the cloud a systematic investigation of the influence of the initial density profile and turbulent motion was performed. For each of four different density profiles and six velocity fields a three-dimensional collapse simulation was carried out in order to examine the cloud evolution, the fragmentation process, the number of formed protostars and the accretion onto these protostars. The density profiles contain a top-hat, two power-law and a Bonnor-Ebert-like distribution; the supersonic turbulent motions are a composition of random velocity fields with solenoidal, compressive or mixed modes with rms Mach numbers of around 3, leading to a fraction of kinetic to potential energy of 5 to 10 percent. For all simulations a dense core with a radius of 0.1 pc and a total mass of 100 solar masses was set up, using an isothermal equation of state at a temperature of 20 K. The effective resolution of the computed box was 4096^3 cells, corresponding to a smallest cell of 13 AU. The cloud is composed of gas with a solar abundance and a molecular weight of 2.3. The local collapse process is implemented with sink particles that accrete material inside a radius of roughly 40 AU. | |
| Collaborators: R. Banerjee, ITA Heidelberg, Germany R. Klessen, ITA Heidelberg, Germany |
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