The Relationship Between the Dust Condensation Sequence for Oxygen-rich Circumstellar Environments and the C/O Ratio
Abstract
The C/O ratio of dust-forming regions around AGB stars is one of the factors in determining the astromineralogy of the dust. It has been suggested that expected variation in the C/O ratio even within oxygen-rich environments should cause subtle changes in the condensation sequence. Such changes will manifest themselves in the spectral features associated with these environments.
We are investigating this hypothesis by studying the relationship between C/O ratio and the parameters of the emission features in the spectra between 9 micron and 12.5 micron (such as 10 micron silicate emission feature) of oxygen-rich AGB. C/O ratio values have been collated directly from the literature and in some cases, have been estimated using published abundance data. The spectra data were obtained from IRAS-LRS and ISO-SWS archives. The parameters of the emission features (e.g.: peak wavelength, fitted FWHM, etc) have been determined using a variety of techniques including continuum fitting. Detailed data analysis has been preformed. Preliminary insight includes that there is a slight trend towards large FWHM as C/O decreases if C/O less than 0.48 (solar abundance). The effect of the C/O ratio on the parameters of the spectral features is minimal. The feature at 10.6-10.8 micron implies that some crystalline silicate is present. Further insight and discussions will be presented.- Publication:
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American Astronomical Society Meeting Abstracts #215
- Pub Date:
- January 2010
- Bibcode:
- 2010AAS...21543112C