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Planet 48

Characterization of young accreting planets (Part I)

Principal Investigators

  • Prof. Dr. Sebastian Wolf
    Christian-Albrechts-Universität zu Kiel, Kiel
  • Prof. Dr. Hubert Klahr
    Max-Planck-Institut für Astronomie, Heidelberg


We will study the feasibility and best strategy to observationally constrain

  • Key properties of young, accreting planets during the final phase of their formation (mass, effective temperature, luminosity, spectrum)
  • Physical conditions of the gas and dust phase (spatial density and temperature distribution, velocity field) as well as the dust properties and gas composition in the immediate environment of the accreting planet.

This project will link observations of accreting planets to physical quantities. Eventually, this study will provide the link between the well explored regimes of early stages of planet formation/disk evolution and mature planetary systems. This is a timely project, as recent high-contrast, high-angular resolution observations have already revealed first signatures of accreting (proto-)planets.


Anton Krieger, Julio David Melon Fuksman


Our studies are based both, on analytical models for the gas and dust distribution around young accreting protoplanets, as well as on distributions resulting from hydrodynamic simulations. In either case extremely high optical depths on small spatial scales made the development of an optimized approach to solve the radiative transfer problem necessary.

In the regime of high optical depths this approach encounters difficulties since a proper representation of the various physical processes can only be achieved by considering high numbers of simulated photon packages. Our newly developed method aims at solving the problem of high optical depths which relies solely on the use of unbiased Monte Carlo radiative transfer.

We carry out a performance test of the method to confirm its validity and gain a boost in computation speed by up to three orders of magnitude. Applying the new method to a model of a viscously heated circumstellar disk, we find that the impact of an incorrect treatment of photon packages in highly optically thick regions extents even to optically thin regions, thus, changing the overall observational appearance of the disk (Krieger & Wolf 2020). Consequently, this finding is essential for the primary goals of this project.

Unbiased Monte Carlo continuum radiative transfer in optically thick regions

Invited Guests


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