Resolving gas and dust in transitional disks: the ALMA view on planet formation
Nienke van der Marel

Protoplanetary disks of gas and dust around young stars are the birth cradles of planets. The study of these disks was for a long time based on unresolved observations, limiting our understanding of planet formation. Of particular interest are the so-called transitional disks with inner dust cavities, a sign of active evolution. The arrival of ALMA has revolutionized our view of the structure of these disks. ALMA observations in the last few years have revealed rings, asymmetries, dust/gas segregation, gas dynamics, evidence for dust trapping and vortices, and many more exciting phenomena that have been predicted for decades in disk models. Using new physical-chemical modeling tools it is now possible to constrain gas and dust densities and compare these with planet-disk interaction model predictions. In this talk I will discuss several recent ALMA discoveries and the next steps in planet formation studies.