5 mars 2021
Title: Modeling of protoplanetary disks physics and chemistry
Speaker: Dr. Maxime Ruaud (NASA postdoctoral program fellow, NASA Ames Research Center)
Abstract: The chemical composition of protoplanetary disks is inherited from their parent molecular clouds, but is expected to significantly evolve during the stages of planet formation. Disk chemistry not only dictates the inventory of material that gets assembled into planets, but also determines the abundances of species with bright, easily detectable emission lines. Gas line emission offers a window into the assembly process by allowing us to infer the physical conditions in the disk during planet formation epochs. Many disk properties, including fundamental ones such as gas mass and bulk elemental abundances are in fact inferred from these emission lines. For instance, recent studies on disk chemistry have inferred changes in the C/O and C/N ratios of disks, with implications for planetesimal formation and the composition of exoplanet atmospheres. These inferences are primarily based on ALMA detections of bright emission lines from trace species such as CO, C2H and CN and are linked . While these studies propose a direct link between the molecular emission observed in disks and planet formation processes, the use of these species to infer disks properties and chemical composition presupposes a good understanding of the chemistry taking place in disks, both in the gas phase and also in ice of dust grains. In this presentation I will show recent results obtained from a framework in which we self-consistently solve the time dependent gas-grain chemical composition of disks with a structure obtained from self-consistent thermo-chemical disk modeling including dust physics and detailed photochemistry. Based on these results, I will discuss the importance of using detailed models for interpreting past and future observations obtained from ground and space-based observatories such as ALMA, the IRAM or JWST.