Transformations in planet formation with ALMA: zooming in on transitional disks

Protoplanetary disks of gas and dust around young stars are the birth cradles of planets. Of particular interest are the so-called transition disks with large inner dust cavities, a sign of active evolution and potential early planet formation. 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. Larger disk surveys allow us to compare disk results with exoplanet statistics. In this talk I will discuss several recent ALMA discoveries and the next steps in planet formation studies.