Mathematics
Scientific paper
Dec 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003phdt.........1f&link_type=abstract
PhD Thesis, Naturwissenschaftlich-Mathematische Gesamtfakultät der Universität Heidelberg, Germany. III + 143 pp. (2003)
Mathematics
3
Circumstellar Matter, Dust, Extinction, Stars: Mass-Loss, Stars: Winds
Scientific paper
During the final stages of their evolution most stars become efficient dust factories. On the Asymptotic Giant Branch (AGB) low or intermediate mass stars loose most of their initial mass in a massive stellar wind and develop optically very thick dust shells. Dust is very important for stellar evolution since only dust particles cause efficient gas cooling during the protostellar collapse. Therefore dust formation influences directly the evolution of stars and further evolution of galaxies. In this work condensation of dust grains were investigated under mass loss conditions for stars with different element abundances and metallicities. The process of dust formation for S stars were studied. It could be shown, that FeSi, metallic iron, and small quantities fosterite and SiC condense for S stars. The dependence of composition of the mineral mixture from the Mg/Si abundance ratio in stellar shells around giant stars of spectral type M were investigated. It was found, that formation of quartz can be expected for magnesium poor stars and that this dust component can be identified by characteristic spectral features of quartz in the infrared spectrum of the dust shell. Further the condensation of Fe and Mg oxide and of the solid solution magnesiowüstite (MgFeO) in the stellar wind of ABG giants and RGB supergiants with oxygen rich element mixture were studied. Calculations show, that magnesiowüstite is a likely condensate. The calculated wavelength of the magnesiowüstite resonance corresponds to a unidentified dust feature found in some oxygen rich circumstellar dust shells. Finally mass loss on the AGB and dust formation rate as well as the quantities of dust produced by evolved stars were investigated via synthetic AGB evolutions.
No associations
LandOfFree
Staubbildung in Sternwinden does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Staubbildung in Sternwinden, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Staubbildung in Sternwinden will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1550217