The very successful ISO mission provides for the first time complete and multi-epoch spectroscopic observations of C-rich AGB-variables. The large wavelength coverage of the Short Wavelength Spectrometer (SWS, de Graauw et al. 1996) allows us to simultaneously study the molecular features and the emission from circumstellar dust and their variation with pulsational phase. In view of the strong interplay between gas and dust predicted by models, this aspect is of special importance.
First guaranteed time ISO-SWS observations of several carbon stars have been presented by Yamamura et al. (1998). They mainly compared the observed spectra of stars with different mass loss rates. In this paper we concentrate on the variation of molecular absorption features. We give the first comparison of dynamical model atmospheres for C-rich stars with ISO-SWS observations and hence a first check of the predictions made by these time-dependent models. In forthcoming papers we will discuss in more detail the interaction between absorption band intensities and variations of the dust features.
© European Southern Observatory (ESO) 1998
Online publication: June 26, 1998