PSI-COM · Photo Stability of Ice-bound Complex Organic Molecules

The universality of life i.e. the likelihood that life can form in extra-terrestrial environments hinges upon the availability of certain molecular building blocks. Whether the biomolecules of which we are made form before or after planet formation is an open question in astrochemistry; answering this question requires an understanding of the life cycle of biomolecular precursors (BPs) in various circum- and interstellar environments. Numerous complex organic molecules (COMs) with biological significance have been identified in star- and planet-forming regions through astronomical observations, motivating laboratory studies aiming to uncover the mechanisms by which prebiotic molecules are born during the early stages of planetary evolution. However, formation of BPs can only partially answer questions regarding the likelihood of life evolving elsewhere in the universe. It is also critical to understand the stability of such species in the harsh environment of the interstellar medium (ISM).Whether small BPs would have sufficient lifetimes in the ISM to eventually coalesce into larger COMs is the central question of this research proposal, which concerns the Photo-Stability of Ice-bound Complex Organic Molecules (PSI-COM). Laboratory experiments on interstellar ice analogues containing selected BPs will be performed using a fully operational and highly-specialized ultra-high vacuum apparatus. Ices will be bombarded with ultraviolet radiation characteristic of that produced in dense interstellar clouds as well as in the diffuse ISM, and the chemical evolution will be tracked to yield kinetic and mechanistic information useful to astronomical models of star and planet formation. The results will be compared with or used to steer observational studies, such as the James Webb Space Telescope.