English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We have carried out a quantitative trend analysis of the crystallinesilicates observed in the ISO spectra of a sample of 14 stars with differentevolutionary backgrounds. We have modeled the spectra using a simple dustradiative transfer model and have correlated the results with other knownparameters. We confirm the abundance difference of the crystalline silicates indisk and in outflow sources, as found by Molster et al. (1999, Nature 401,563). We found some indication that the enstatite over forsterite abundanceratio differs, it is slightly higher in the outflow sources with respect to thedisk sources. It is clear that more data is required to fully test thishypothesis. We show that the 69.0 micron feature, attributed to forsterite, maybe a very suitable temperature indicator. We found that the enstatite is moreabundant than forsterite in almost all sources. The temperature of theenstatite grains is about equal to that of the forsterite grains in the disksources but slightly lower in the outflow sources. Crystalline silicates are onaverage colder than amorphous silicates. This may be due to the difference inFe content of both materials. Finally we find an indication that the ratio ofortho to clino enstatite, which is about 1:1 in disk sources, shifts towardsortho enstatite in the high luminosity (outflow) sources.

Crystalline silicate dust around evolved stars