My work focuses on a class of astronomical objects called protoplanetary disks. These flattened structures rotating around young stars are made of gas and dust and are the places where planets,... Show moreMy work focuses on a class of astronomical objects called protoplanetary disks. These flattened structures rotating around young stars are made of gas and dust and are the places where planets, like our own Earth, are formed. One of the main properties needed to explain the process of planet formation is the mass of protoplanetary disks. There is however not yet a consensus on how such masses can be reliably measured from disk observations. In this thesis, I investigate weather less abundant isotopologues of carbon monoxide (CO) are good candidates for tracing disk masses. Initially I tackle the problem from a theoretical point of view by running a grid of physical-chemical disk models. Subsequently I compare my model predictions with recently acquired observations of protoplanetary disks in the Lupus star-forming region. The conclusion of my work is that CO isotopologues are good disk mass tracers, but they need to be calibrated. Observations of other molecules like hydrogen deuteride (HD), atomic carbon and hydrocarbons can serve this cause. Show less
