Protoplanetary discs and their environs: the synergy between observation and theory in the era of ALMA
Cathie Clarke

The last decade has witnessed unprecedented advances in the observational characterisation of protoplanetary discs and their nascent planetary systems, thanks in large part to the transformative capabilities of ALMA (the Atacama Large Millimetre Array). In the first part of my talk I will describe how the relatively simple physics governing the dynamical evolution of drag coupled dust grains plays a crucial role in interpreting disc imaging data and will describe progress in `weighing' planets in discs, measuring their migration and assessing the role of chemical transport on grains in driving the ambient chemistry in planet forming regions. In the second part of my talk I will turn to the question of possible environmental effects that govern the evolution of protoplanetary discs. This question is answered through detailed calculations both of the possible role of star-disc encounters and also of Far Ultraviolet Photoevaporation in limiting disc lifetime and I describe how the latter is the overwhelmingly dominant environmental factor in all star forming regions. I will conclude by discussing how such calculations can be observationally tested, both through disc demographic surveys in relatively distant, strongly irradiated star forming regions and via detailed characterisation of disc kinematics in regions with intermediate distances and ultraviolet fluxes.