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2023-11-28 Bertram Bitsch (UCC)

Planet formation in the JWST era

Protoplanetary discs surrounding young newborn stars consist of gas and to a small fraction of dust. These micro meter sized dust grains can then grow to become mm-cm sized pebbles, which drift inwards due to gas drag. The pebbles themselves can form planetesimals (10-100km sized objects), which can further grow by accreting the leftover pebbles. Once the planetary core grows to 10 Earth masses, it can attract a gaseous envelope and become a gas giant. This overall growth process is know as the core accretion scenario and it can reproduce the majority of the observed exoplanets. However, this scenario is now challenged by observation of the planetary atmospheres.  It is thought that the atmospheric composition of planets holds key to their formation location, where especially the C/H, O/H and C/O of the atmospheres are key ingredients, as these ratios vary with orbital distance from the star due to the evaporation of different oxygen and carbon bearing species like H2O, CO2, CH4 and CO. In this talk I will present a state-of-the-art model that allows tracking of the chemical components of the disc and inside of growing planets. I will first explain the ingredients of this model and then show its applications to the composition of discs and forming planets and how this depends on the formation environment.