Undersökning av döende stjärnor: Massförlust och molekyler för stjärnor på den asymptotiska jättegrenen

Examensarbete för kandidatexamen

Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12380/256820
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Type: Examensarbete för kandidatexamen
Bachelor Thesis
Title: Undersökning av döende stjärnor: Massförlust och molekyler för stjärnor på den asymptotiska jättegrenen
Authors: Gustafsson, Johan
Hirvonen, Per
Strömfors, Amanda
Wäpling, Sara
Abstract: The study aims to investigate the mass outflow from evolved stars. Emission lines from nine stars, observed under the project DEATHSTAR, were studied. The gasmass- loss rates were approximated using a simplified formula based on the rotational emission lines of 12CO. Furthermore, the project aims to determine the molecular composition of two of the nine stars, W Hya and R For. The calculated gas-mass-loss rates varied from 10−7 to 10−5M yr−1. The dust-mass and dust-mass-loss rate calculations were only attempted regarding the star W Hya, though no dust-mass and dust-mass-loss could be determined from the data. The observed emission spectra from W Hya and R For contained at least 16 and 17 molecular emission lines respectively. The outflow of W Hya is dominated by oxygen based molecules, while the outflow of R For contains carbon based molecules. Finally, the emission lines from 12CO for several stars show evidence of asymmetric envelopes. The obtained profile for R Hya hints at multiple velocity components and might warrant a more in-depth investigation in the future.
Keywords: Fysik;Astronomi, astrofysik och kosmologi;Physical Sciences;Astronomy, Astrophysics and Cosmology
Issue Date: 2019
Publisher: Chalmers tekniska högskola / Institutionen för rymd-, geo- och miljövetenskap
Chalmers University of Technology / Department of Space, Earth and Environment
URI: https://hdl.handle.net/20.500.12380/256820
Collection:Examensarbeten för masterexamen // Master Theses

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