OCEANS · Origin and Composition of Exocomets Around Nearby Stars

The presence of exocometary gas in young (10-100 Myr) debris disks presents a unique opportunity to probe the composition of exocomets during the late stages of terrestrial planet formation. This is the evolutionary stage when ice-rich impacts are proposed to change the volatile environment of terrestrial planets, setting the stage for prebiotic chemistry.This action will establish a new paradigm of Exocometary Science as a unique tool for probing the composition of planetary systems in the crucial, last period of terrestrial planet formation. I will expand current observational approaches, focused on observations of CO gas at millimetre wavelengths, to UV and IR wavelengths, in order to access atomic and yet unseen molecular species, including water, to probe the entire chemical variety of exocomets. In doing so, I will exploit existing observational facilities and prepare for upcoming sensitive observatories such as JWST. Additionally, I will study the origin of exocomet compositions - so far consistent with Solar System comets - and their link to a potentially common belt formation location in young protoplanetary disks. This action will set the stage for compositional inventories of exocomets, allowing us to put our Solar System comets into the broader context of extrasolar planetary systems, exoplanets and young disks, and providing a missing link in the study of planet formation and physical-chemical evolution.