Abstract

Recent discovery of exocometary gas in extrasolar Kuiper belts has opened the field of exocometary science. Comets carry the basic volatiles required for the development of life as we know it, meaning that young exocometary belts provide a unique window into volatile delivery to rocky planets in the final stages of their formation. In this talk, I will show how exocometary gas detection and volatile characterisation are now possible, thanks to the advent of sensitive observatories such as ALMA . In particular, I will present modelling and observational work aimed at detecting low levels of molecular gas and determine its exocometary origin, focusing on the belts around nearby stars Fomalhaut and beta Pictoris. I will show how to derive gas masses and translate them to cometary abundances, allowing a first comparison of the volatile reservoir of exoplanetary systems to that of our own Solar System, already indicating similarity. Finally, I analyse the resolved structure of the observed gas and compare it to predictions from dynamical models. To conclude, I will propose directions in which to develop the field in order to better understand the volatile composition, origin and properties of exocometary belts around nearby stars.