Emelie Siderud (Uppsala University): Stellar winds of carbon stars: The role of dust optical properties (Licentiate)

Friday 1 Dec 2023, 13:15 → 15:15 Europe/Stockholm

Title: Stellar winds of carbon stars: The role of dust optical properties

Friday 1 December at 13:15

Room 4001 (Ångström)

Subject reviewer: Prof. Anja Andersen from University of Copenhagen

 

Abstract: Stars with initial masses of about 0.8-8 solar masses go through an asymptotic giant branch (AGB) phase before reaching the end of their lives. During this phase, they undergo extensive mass loss in the form of a stellar wind, ultimately shedding their entire outer envelopes. The winds are driven by radiation pressure exerted on dust grains in the outer atmosphere.   For carbon-rich AGB stars, the primary wind-driving species is amorphous carbon (amC), a structurally complex material. Numerous laboratory studies have synthesized amC dust, providing a range of available optical data. This thesis explores the influence of optical data derived from synthesized dust on the atmosphere and wind models of AGB stars. Large grids of models, with a range of input parameters, are computed using state-of-the-art radiation-hydrodynamical modelling. The micro-physical properties of dust grains are demonstrated to influence not only wind dynamics but also grain sizes and photometric properties.