Giant Planets Evolution

Researcher: Allona Vazan

Supervisors: Morris Podolak, Attay Kovetz, Ravit Helled

I modeled the evolution of giant and intermediate mass planets, formed by core accretion or gravitational instability mechanisms. I focused on the influences of the heavy components, like rocks and ices, on the evolution of the planets by considering their contribution to the energy and also to the opacity. For that purpose I used a stellar evolution quasi-hydrostatic code (Kovetz et al. 2009) modified to work under planetary conditions. In order to consider the effect of the heavy component on the heat transfer during the planetary evolution I developed a simplified opacity calculation for grains mixed with gas for different grain sizes and compositions, and heavy element mass fractions.


I have also studied the influence of the protoplanetary disk on the protoplanet evolution. For this work, I considered several protoplanetary disks, and included their pressure and irradiation conditions in different distances from the star in our evolution models. I also simulated the process of gas accretion from the disk, and studied its effect on the final mass and survival of the protoplanet. In order to model the gravitational instability scenario we inserted into the evolution code an instability criterion for dynamical scale changes during evolution which allowed the protoplanetary clump to undergo a "dynamical" collapse.


Currently I am studying the redistribution of heavy elements within the planet during its evolution. I am modeling the core erosion scenario and its effect on the heat release and therefore on the evolution and inner structure of planets. In this work, I calculate for different initial inner structures (depending on the formation process) the convective-mixing of components and energy during evolution. The mixing of materials is calculated using the Mixing Length Recipe, and the convective instability criterion is determined by the Schwarzschild or Ledoux criteria.


I am also interested in exploring the effect of the protoplanetary disk metallicity on the formation and evolution of planets embedded in the disk. I am testing several cases of protoplanets with different metallicities in the pre-collapse phase and would like to examine the influence of the heavy element and planet-disk interaction.


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