TY  - GEN
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/36856/
ID  - heidok36856
TI  - Warped Disks in 3D ? From the formation and evolution to synthetic observations
A1  - Kimmig, Carolin Nadja
Y1  - 2025///
CY  - Heidelberg
AV  - public
N2  - Planets are born in disks around young stars called protoplanetary disks. It is therefore essential to understand the physical and dynamical conditions dominating these disks. In the past decade, highly resolved observations of protoplanetary disks have transformed the research field. Many observations revealed striking non-axisymmetric structures. Some of these structures can be explained by a shadow cast from a possibly unresolved misaligned inner disk region. The abundance of such observed shadows suggests that misalignments might be common.

In this thesis, I investigate the formation, evolution and appearance of warped protoplanetary disks. To study their dynamics, I use three-dimensional grid-based simulations, a method which is not commonly used in previous models of warps. I therefore extensively test its applicability to disks misaligned with the intrinsic geometry of the grid. I find that warps can be modeled accurately under the condition of a sufficient vertical resolution. My simulations show the expected wave-like warp evolution and additionall reveal an internal twisting of the disk, which is not included in standard one-dimensional models. My various tests suggest that the twisting is a physical effect intrinsic to the three-dimensional warp evolution.

I apply the grid-based method to a formation scenario of warps: inclined stellar fly-bys. I first investigate different configurations of the fly-by trajectory with respect to the disk. The simulations show that inclined fly-bys can excite a warp of a few degrees which can last for over ten thousand years. I then model RW Aur A, an observed star-disk system that recently experienced a close encounter with another star with a well constrained trajectory. My models show that a warp of about 5° misalignment is excited, which is consistent with the observations.

Shadows, mainly observed in scattered light observations, can give insight into the warp shape. In order to find limits on the observability of warps, I investigate the shadows in radiative transfer simulations of disks viewed edge-on, where warps can cause asymmetries. I find that under optimal conditions, small warps with a misalignment of only 2° can create observable asymmetries. As the strength of the asymmetry depends on the orientation of the warp with respect to the observer, it remains challenging to infer constraints on warps from observations. However, rare orientations can lead to a brightness swap between the disk surfaces, a clear indication of a warp, which is observed in a handful of disks.
ER  -