DEATHSTAR – A new hope for accurate mass-loss-rate estimates for AGB stars

Mass loss via a stellar wind is a critical process that governs the later phases of stellar evolution. Through this wind, Asymptotic Giant Branch (AGB) stars are major contributors of newly synthesized elements and dust to their host galaxy. Accurate characterization of this phenomenon is therefore key to advancing our understanding of the Galactic chemical enrichment and evolution. The Deathstar project aims to provide a definitive description of AGB gas mass loss by mapping the winds of nearly 70  AGB stars in the southern hemisphere using ALMA observations of CO lines. Leveraging ALMA ACA's capabilities, we directly and systematically measured the sizes of the CO envelopes created by the winds, eliminating a major source of uncertainty from wind property estimates. By incorporating these size measurements and utilizing our newly-calibrated distance measurements from Gaia and VLBI parallaxes, we further refine our calculations of mass-loss rates for AGB stars. This poster shows the estimated sizes of the CO envelopes of these nearby AGB stars and their comparison with predictions from photodissociation theory. Additionally, it presents our current work on constraining mass-loss rates using the spatial information from our ALMA observations, showcasing the great value of ALMA for our understanding of AGB outflows.