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Astro Seminar

The outflows of AGB stars as astrochemical laboratories

Speaker: Marie Van de Sande ( Leiden Observatory )
Date: Wednesday 17 January 2024
Time: 14:00
Venue: N3.28/Zoom

During the asymptotic giant branch (AGB) phase, stars with a low-to-intermediate initial mass lose their outer envelope via a stellar outflow to the interstellar medium (ISM). Thanks to their outflows, AGB stars are important contributors to the chemical enrichment of the ISM, contributing about 80% of the stellar gas injection rate and about 70% of the total stellar dust production rate. These outflows are rich astrochemical laboratories: close to 100 molecules have been detected so far, along with some 15 types of newly-formed dust. Understanding the various chemical processes and their link to the dynamics is crucial to our knowledge of the AGB outflows, and feeds into our understanding of stellar evolution and the chemical evolution of the ISM. Recent observations have confirmed the molecular richness and dynamical complexity of AGB outflows and emphasised the intricate interplay between chemistry and dynamics. In this seminar, I will talk about the importance of chemistry to launching the outflow, chemical modelling feeds into interpreting recent observational results, more specifically those of the ALMA Large Programme ATOMIUM, and which major steps still need to be taken.