Origins of planetary systems: Constraints and challenges

The study of planet formation is a field that uniquely benefits from both astronomical observations and laboratory studies of primitive meteoritic material left over from the forming Solar System. We concisely review the key constraints from these studies and place them in the frame of the theoretical models. Four major open problems are identified that can be addressed with next-generation ground-based telescopes: (1) The injection of radionucleids to protoplanetary disks; (2) Protostellar collapse and the formation of the first solids; (3) Thermal processing of protoplanetary materials; (4) Disk-planet interactions and disk dispersal.