Research

Magnetic fields generally do not affect the motion of fluids in our everyday lives. However, the inner regions of protoplanetary disks (including the region where Earth is located today) reach high temperatures of up to several thousand Kelvin, causing the material to become partially ionized and form a plasma. As a result, the omnipresent magnetic fields interact with the disks, which has a decisive impact on the evolution of the disk and the future planets.

Using non-ideal MHD simulations with the PLUTO code, I am investigating how protoplanetary disks respond to different magnetic fields and how magnetic winds and magnetic flux differ. A novel approach is that, instead of simple power-law assumptions for the temperature profile, I use a realistic temperature profile inspired by radiative transfer simulations. These differ in particular in the region of the disk’s condensation front and produce significant differences in disk evolution.

We found that the magnetic wind is activated above a certain magnetic field strength and that the disk atmosphere can be divided into three dynamically distinct regions Bahrenberg et al. (in prep.)

Even though several thousand exoplanets have already been detected, in most cases only their mass and radius can be determined. Despite this limited information, it is possible to make statistical inferences about the planets’ internal composition. To this end, ExoMDN was developed, a neural network that was trained on millions of synthetic planets whose internal structure is known. I improved the atmospheric model of these synthetic planets and demonstrated that the new model results in significant differences in the mass-radius relationship. This paves the way for a more realistic assessment of the internal structure of exoplanets as part of the future PLATO mission (ESA).

The results of this work were presented at the European Geosciences Union, Vienna, Austria in 2025 (Baumeister, Bahrenberg et al. 2025).

Although often referred to as protoplanetary disks, many observations reveal significant deviations from a disk-like structure. One example are so-called “warped disks,” in which the inner and outer regions are misaligned but smoothly connected. This can result, for example, from embedded, inclined planets, stellar flybys, or strong magnetic fields at the inner edge. Scattered light observations reveal impressive interplay of light and shadow, depending on the exact shape of the object. I performed Monte Carlo radiative transfer simulations with RADMC-3D to produce synthetic images of several disk geometries, which allows us to trace the disk structure back from observed shadows. Furthermore, and for the first time, I combined hydrodynamic and radiative transfer simulations of the evolution of warped disks to predict how disks would evolve over time in observations.

The hydrodynamical disk evolution was computed with dwarpy (Kimmig, Dullemond, Bahrenberg, in prep.).