Miora Andriantsaralaza (Uppsala University): Mass loss of evolved stars (Pre-Defence Seminar)

Thursday 14 Dec 2023, 14:00 → 15:00 Europe/Stockholm

Title: Mass loss of evolved stars
Speaker: Miora Andriantsaralaza
Affiliation: Uppsala University
Time: Thursday 14 December 2023, 1400 to 1500
Location: 80127Å

Abstract: When low- and intermediate-mass stars reach the end of their lives, they develop massive winds. Through these winds, material that is enriched with new elements formed inside the star is thereby ejected into the interstellar medium. Investigating this mass loss phenomenon is, therefore, crucial for advancing our understanding of stellar evolution and the chemical enrichment of the Galaxy. DEATHSTAR is a large project aimed at improving the accuracy of wind-parameter measurements of evolved stars on the Asymptotic Giant Branch (AGB). Leveraging ALMA Compact Array's capabilities, we directly and systematically measured the sizes of the CO envelopes created by the winds of a sample of nearly 70 nearby AGB stars, eliminating a major source of uncertainty from wind property estimates. By incorporating the spatial information from ALMA and using our newly calibrated distance measurements from Gaia and Maser parallaxes, our goal is to enhance the accuracy of AGB mass-loss rate estimates. In this presentation, I will provide an overview of the DEATHSTAR project, highlighting our results and conclusions regarding the sizes and distances of our sample of AGB stars. I will also discuss the current status of the project and present some preliminary results from dust and gas modelling.