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Astro Seminar: Ice Mapping in the JWST Era

Seminar by Helen Fraser (Open University)

Event details


It is often overlooked that the largest reservoir of molecular material in star-forming regions is the frozen-out solid-state material, dominated by H2O, CO and CO2 ices. With the JWST ERS programme ICEAGE, GT programmes and subsequent observer cycles, we have observed a number of pre-stellar and star-forming molecular clouds to “map” the  distribution of solid state material in the cloud(s). Focusing on Chameleon I, I’ll be showing the resultant ice maps, and discussing the new astrophysics (and astrochemistry) we can glean from these observations only as a result of ice spectroscopy. JWST is an unprecedented telescope for observing ices – but its not always easy to get from the raw data to the observations. I’ll briefly explain our 4-year development of the ice-mapping techniques and show what we can learn from the first large statics in ice spectroscopy in a single cloud, instead of looking at isolated lines of sight.

The pre-stellar and star forming cores are only the first stage of the star-formation process. By coupling features in the ice spectroscopy with those in. gas and dust observations of the same regions we are unravelling information on dust aggregation, and the “journey” of molecular material from the ISM into planet forming protostellar discs around YSOs. In these very early evolutionary, in pre-stellar cores and through to regions around the snow lines in discs, the aggregation of icy grains is assumed yet poorly explained by physics (and models). We take an empirical approach to study icy grain aggregation – I’ll also show some of our latest laboratory data on grain collisions– of icy grains and even fluffy amorphous grains – showing the kinds of data we can generate to constrain models and processes – including collision induced outgassing from grains as they collide.


Physics Building 4th Floor