In star-forming regions chemical processes progress on timescales similar to those of other physical processes governing star (and planet) formation. However the ingredients of stellar systems are set long before these processes begin, in the dense dark regions of interstellar clouds. Seemingly ubiquitous across our own galaxy (and as resolution improves – in interstellar regions of the nearest galaxies) molecular chemistry dominates these chemical processes. The largest reservoir of molecules is in fact not the CO gas (or other chemical tracers) you might expect, but after H2 gas – the solid-state species – H2O CO and CO2 – the most common molecular ices in space. These ices play a pivotal role in both the formation of complex organic species (COMs) used to trace gas-phase chemical complexity as star-formation progresses, and ices are the most likely candidate to form the “glue” leading to particle aggregation at the earliest stages of planet formation.
Observing condensed molecular solids is a real challenge – and I’ll explain the novel observing techniques we are using for this, and how the JWST era will revolutionize our understanding of icy astrochemistry. Linking ice observations back to gas and dust observations to uncover the astrochemistry and explaining what we can learn from such observations will be at the heart of my talk. Slightly different from cosmology, but as the JWST era evolves, combining JWST ice-observations
with ALMA observations is going to trace not only the spatial distribution of such species together with their “look back” reach – enabling astronomers to ask “when did the first complex chemicals appear in the galactic fossil history” and “how is chemistry linked back to the earliest stages of star and galaxy formation?”.