DFG Schwerpunktprogramm 1385

DFG Schwerpunktprogramm 1385

Streaming instabilities are a result of sufficient dust densities and large relative flow velocities between dust and gas. This instability itself produces the turbulence that makes it possible to clump dust sufficiently together in order to become self-gravitating and thus overcome the meter-barrier in planet formation. This mechanism is thus of significant interest for the scientific community.

Members working on this project

White: Gas density, Red: Gas density.
Note how gas concentrations follow high-pressure regions and become elongated along the shear flow.

Before gravitationally stable planets are born planetesimals of 100 kilometres in size must have formed in the protoplanetary disk around a new born star. In my hydrodynamical simulation I examine different physical parameters and different formation processes for such planetesimals within protoplanetary disks, with special focus on dust streaming instabilities.

In those simulations I investigate the regime of high dust-to-gas ratios on very small physical scales, below a tens of a disk scale height. I observed streaming instabilities being still active even at very high dust concentrations, which are present in the collapse phase of a Roche density particle heap.

I now try to derive effective diffusivity values for this situation and with that we will be able to calculate the efficiency of the collapse scenario. Additional planetesimal formation studies are planned, such as the impact factor of collision velocity and Rayleigh-Taylor simulations of segmenting dust clumps. Simulations are performed on Hydra and JUQUEEN superclusters using the Pencil Code.

Resources provided by Andreas Schreiber

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