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| Paper: |
Grain Nucleation Experiments and Other Laboratory Data |
| Volume: |
445, Why Galaxies Care about AGB Stars II: Shining Examples and Common Inhabitants |
| Page: |
215 |
| Authors: |
Andersen, A. C. |
| Abstract: |
In order to interpret observations influenced by dust and to perform
detailed modeling of the observable characteristics of dust-producing
or dust-containing objects, knowledge of the micro-physical properties
of relevant dust species are needed. Laboratory measurements of cosmic
dust analogues provides essential input for our understanding of how
dust particles can influence the dynamics and thermodynamics of the
stellar atmosphere by their opacity.
The formation of the dust grains influences the stellar atmosphere in
two ways. In the gas phase chemistry, dust formation results in a
depletion of certain elements, which influences the molecular
composition of the gas and consequently the corresponding opacities.
On the other hand, dust grains have a rather high mass absorption
coefficient, which often may be comparable to the gas opacity or even
exceed it. Due to its high opacity and the resulting radiative pressure,
the dust has a strong influence on the structure of the atmosphere and
the wind properties of AGB stars.
Great care is needed when obtaining laboratory data as even a moderate
variation of the different micro-physical dust values within the range
expected for possible materials has noticeable consequences for the
interpretation of the near-infrared colors of AGB stars. |
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