Constraining the turbulence and the dust disk in IM Lup: onset of planetesimal formation

Riccardo Franceschi

Thursday, Dec. 8th, 14:40CET

Observations of protoplanetary disks provide information on planet formation and the reasons for the diversity of planetary systems. The key to understanding planet formation is the study of dust evolution from small grains to pebbles. Smaller grains are well coupled to the gas dynamics, and their distribution is significantly extended above the disk midplane. Larger grains settle much faster and are efficiently formed only in the midplane. By combining near-infrared polarized light and millimeter observations, it is possible to constrain the spatial distribution of both the small and large grains. SPHERE scattered light observations of the disk around IM Lup distinctly show the disk surface in the near-infrared emission. We couple this data to millimeter ALMA midplane emission to construct a detailed model of the size distribution and vertical/radial structure of the dust particles in the disks. We use a Markov chain Monte Carlo method to compare the model radiative transfer images to the SPHERE and ALMA data and constrain the best physical model for IM Lup.