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Paper: |
A Spitzer Sample of S-type AGB Stars |
Volume: |
445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants |
Page: |
209 |
Authors: |
Smolders, K.; Blommaert, J.; Decin, L.; Van Winckel, H.; Hony, S.; Sloan, G.; and the Spitzer S-star group |
Abstract: |
We present a set of Spitzer IRS spectra (5–35 μm) of a
sample of intrinsic S stars, covering the entire MS–S–SC sequence.
We acknowledge that, due to the selection criteria employed, the
sample is biased towards lower mass-loss rates. Most stars do not show
significant emission features. For the dust-rich stars, we can conclude
that the dust resembles the dust around M stars, with alumina,
silicates and magnesium-iron-oxides as the strongest emission features.
Furthermore, we detect PAH emission features in four S stars and
confirm the correlation between the temperature of the central star
and the centroid wavelength of the 7.9 μm feature. We argue that
the mixture of hydrocarbons we see in these S stars has a rich
aliphatic component. |
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