Abstract

The initial conditions for the origins of life are set long before a planet exists, in interstellar clouds where water first forms, and icy grain chemistry efficiently converts C, CO, and CO2 into a range of organic molecules. If these survive the perilous journey from cloud to planet, they may profoundly influence the subsequent prebiotic chemistry both on the young Earth and on potentially habitable exoplanets. This talk will review what we know of interstellar organic reservoirs from astronomical observations, and then introduce how such molecules may form at 10 K, focusing on the role that excited atoms, radicals, and molecules may play in this interstellar organic ice chemistry. We will next consider whether interstellar water and organics are likely to survive the different stages of star and planet formation, and how we can use isotopic fractionation to track their journey from cloud to planetesimal. Finally, we will consider under which planetary conditions interstellar organics are likely to play a decisive role in setting the stage for an origins of life chemistry that can convert small organics into biomolecules.