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AEROSOL - 646758;info:eu-repo/grantAgreement/EC/H2020/646758

Abstract:

The generally accepted hypothesis is that the wind driving mechanism of AGB stars is a combination of stellar pulsations and radiative pressure on newly formed dust grains, yet current models still suffer from several limitations. In particular, they assume chemical equilibrium of the gas and apply various simplifications to describe the formation of dust. Currently, no model exists which self-consistently incorporates all physical and chemical processes of an AGB wind. This thesis strives towards developing such a model by reducing the amount of assumptions. The improved model, developed in this thesis, is the first to fully couple time-dependent dynamical and chemical evolution in an AGB wind. Additionally, a revised dust formation description has made it possible to more accurately gauge the viability of specific chemical species as the first AGB dust precursors and has revealed the implications of using simplified formation descriptions. This thesis also contains all the ingredients to include a time-dependent dust size evolution, a dynamical interaction between gas and dust, and a treatment of the radiation force acting on the dust grains. Combining all aforementioned physical and chemical processes into one model, results in a better understanding of the composition and characteristics of gas and dust lost during the AGB phase, and the role of this phase in the chemical life cycle of galaxies and the Universe.