Photometry of carbon star wind-modelsat solar & sub-solar metallicities

Sammanfattning: Asymptotic giant branch stars (AGB) are cool, luminous stars withan initial mass of approximately 0.8 to 8 solar masses. Towards theend of their lives they undergo heavy mass loss, a process thoughtto be caused by dust-driven winds. When it comes to carbon-richAGB stars, i.e. stars with an atmosphere dominated by carbonaceousmolecules and dust, it is believed that the wind is mainly driven byphoton absorption on amorphous carbon grains.This project will focus on how mass loss in carbon-rich AGB stars(C-type) is inuenced by their metallicity. In order to investigate themetallicity-dependence of mass loss I will use state-of-the-art radiationhydrodynamicalwind models that cover a range of typical parametersand metallicities. Since winds of AGB stars are driven by radiationpressure on dust, such wind models can also be used to investigatehow much AGB stars contribute to the dust production in the ISM asa function of metallicity.The aim of this study is to compare theoretical photometric predictionsfrom wind models for C-type AGB stars, at solar and sub-solarmetallicities, to observed photometry. In order to do this the absolutemagnitudes for various lters (GAIA, HST, Vista, WISE, Spitzer andJWST) need to be computed based on synthetic spectra from thesewind models.Once all the theoretical results are obtained these will be comparedto observational data from various surveys of AGB stars in the Largeand Small Magellanic Clouds, covering visual, near-infrared and midinfraredwavelength regions.