Abstract

Over the last decade, the Atacama Large Millimeter/submillimeter Array (ALMA) made it possible to observe protoplanetary discs, the birth sites of planets, at unprecedented angular resolution and sensitivity, revolutionizing our understanding of planet formation. When observed at high-enough angular resolution, protoplanetary discs show sequences of axisymmetric dark and bright substructures, colloquially referred to as “gaps and rings”. The origin of such substructures and the role they play in the planet formation process are, however, still debated. They are considered to be either the signposts of ongoing interactions between discs and their hosting (proto-)planets, or the ideal location for the formation of new planetary bodies. The best way to solve this “chicken and the egg” problem is characterizing the physical properties of these gaps and rings. In this talk, I will first discuss recent attempts to observationally infer the size, density, and temperature of dust in these rings, relying on collecting and modelling multi-frequency, i.e. (sub-)mm to cm, continuum data in a handful of well studied systems. I will then show how dust properties, in combination with gas kinematics, can be used to understand if bright rings are prone to the formation of new planets. Finally, I will discuss how my results can be extended to a statistical level using mid-resolution observations of populations of discs in nearby star-formation regions.