Constraining the physical processes in protoplanetary disks with radiative transfer codes

Séminaire IPAG de Gijs Mulders (U. of Amsterdam), jeudi 15 mars 2012 à 11h00, IPAG seminar room

Protoplanetary disks are thought to be the main sites of planet formation, and to understand how planets form we need to understand the physical processes in these disks. Radiative transfer codes are able to explain a large variety of observations of these disks — both resolved and unresolved — and have become an important tool in modelling them. However, their fit parameters are not always connected to the physical processes we want to study. In this talk I will explain how we can learn more from existing observations by using more and better descriptions of disks physics in these codes.

One of these physical processes is turbulent mixing, which is the main driver of disk accretion. It also manifests itself in dust settling and grain growth - the first steps of planet formation. However, the strength of turbulent mixing is not well known, both from a theoretical as well as an observational point of view. I will show how the turbulent mixing strength can be constrained from unresolved SEDs, and that it does not vary across the stellar mass range. Another physical process is grain growth, which has been directly observed in scattered light images. I will show a new way of extracting grain sizes from these images, and the implications it has for turbulent mixing.