Overview

I am a postdoc at the Harvard-Smithsonian Center for Astrophysics working with Sean Andrews. The general topic of my research is the structure and evolution of protoplanetary disks, the birthplaces of planets. More specifically, I am woking on the dynamics and the size evolution of dust in these disks. Young stars and the disks around them are built up from interstellar matter which contains only very small, i.e. at most micrometer-sized dust particles. This small dust is the material out of which planets form. However the mechanisms which lead to the growth along over 45 orders of magnitude in mass are still poorly understood. The aim of my work is to understand how grains can grow from small to large and how they are distributed and transported in the disk.

I also work together with observers in order to compare my models to observational data and thereby test the theory behind them. The questions we would like to answer are the following:

• What are transition disks (disks with large inner cavities)? Do they host planets or is some other effect the reason for their appearance?
• Can we use dust observations to probe the structure and evolution of protoplanetary disks?
• How can we explain the existence of mm-sized pebbles in the outer regions of disks? How do they form and how do they migrate?
• How does grain growth proceed from sub-µm sized dust to planetesimals? Can we understand this with models based on current laboratory experiments?
• What is the size and structure of so-called dead zones, i.e., regions where the disk is predicted to be non-turbulent and what is the role of fine dust grains in this picture?