In English

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

Johan Gustafsson ; Per Hirvonen ; Amanda Strömfors ; Sara Wäpling
Göteborg : Chalmers tekniska högskola, 2019. 59 s.
[Examensarbete för kandidatexamen]

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.

Nyckelord: AGB-stjära, massförlust, ALMA, ALMA-ACA, stoft, W Hya, R For,molekyler, emissionslinjer



Publikationen registrerades 2019-06-14.

CPL ID: 256820

Detta är en tjänst från Chalmers bibliotek