Contents of: VI/111/./abstract/JGURTLER_STARDUST.abs

The following document lists the file abstract/JGURTLER_STARDUST.abs from catalogue VI/111.
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 We plan to investigate the spatial structure and physical conditions
 around asymptotic giant brach (AGB)stars (semi-regular variables,
 Mira stars). Our sample of targets is composed of objects that
 appear to be in a similar evolutionary stage, judging from the
 spectral type of the star and the IRAS LRS data. This is necessary
 to be able to draw more general conclusions.

 In order to study the spatial structure of the dust shells, we want
 to map all sources at a wavelength of 50 microns. To date, there
 exist only IRAS high-resolution maps for some objects with a rather
 limited quality. It will be the first time that high quality far
 infrared maps will be produced. To make sure that the shells are
 sufficiently extended to be resolved by ISO, we have selected our
 objects from a study that derived the diameter of the dust shells
 from IRAS data. The diameters are typically several minutes of arc.
 For all sources IRAS LRS data exist. The IRAS data indicate that a
 wavelength of 50 microns is ideal to map the envelopes to their
 full extent.

 In addition, we wish to measure the near-infrared spectra from 2.5 to
 12 microns and the IR spectral flux densities at 70, 90, and 120
 microns. We will combine these data with IRAS LRS data to obtain
 complete spectral energy distributions (SEDs). We have available a
 radiation transfer programme to model the SED. We have carried out
 a first successful test for U Orionis (see Fig. 1). The model
 calculations will allow us to determine the physical parameters of
 the envelope (e.g. mass, density and temperature distribution).

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