Dust2Planets · Unveiling the role of X-rays in protoplanetary disks via laboratory astrophysics

The arrival of ALMA and JWST could revolutionize our understanding of planet formation from the observations of protoplanetary disks. But in order to interpret such observations, better models fed by robust laboratory data are urgently needed. However, laboratory experiments designed to study cosmic matter have mostly focused on the first stages of stellar evolution, where molecular clouds are irradiated by ultraviolet (UV) photons from OB stars. The subsequent protoplanetary stage, where young stars vigorously emit X-rays, has been rarely addressed by experiments. Yet X-rays have a larger penetration depth in solids than UV photons, and could enable important photochemical pathways in the evolution of protoplanetary matter. In this project, we aim to quantify the impact of X-rays on protoplanetary dust via laboratory astrophysics. Our goal is to give closure to the question: how do X-rays impact disk evolution and early planet formation?This project will go beyond the state-of-the-art in two directions: via the laboratory simulation of the X-ray spectrum of T Tauri stars, and by pioneering the use of heterogeneous analogs to protoplanetary dust. We will perform a coupled study of both the dust and gas phases following irradiation to quantify the full impact of X-rays. Complex organic molecules resulting from X-ray irradiation and desorption will be compared to cometary and ALMA detections to clarify the disk-comet connection. Analysis of the X-irradiated solids will elucidate the physico-chemical mechanisms of dust growth, key to the evolution of primordial seeds to planetesimals. X-ray photochemical rates on both the dust and gas phases will be consolidated in a new X-ray Astrochemical Database (XRAD). Our laboratory data will shed light on the photochemical evolution of protoplanetary disks and more generally, on other X-ray Dominated Regions in the universe.