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G.M. Wahlgren (Lund Obs.), F. Bruhweiler (CUA/GSFC), M. Eriksson (Lund Obs.), B. McCollum (IPAC/Caltech), A. Rosas (CUA), E.M. Verner (CUA/UDC/GSFC)
We report on early spectroscopic observations of symbiotic stars conducted with the Spitzer IR observatory. Our program, involving IRS spectroscopy and MIPS imagery, and supplemented with the data from other wavelength regions, aims to characterize the gas and dust environments around symbiotic stars. These environments can be very dynamic as a result of high mass loss rates, interacting winds, accretion disks, jets, and eruptive events. The physical extent of warm and cool gas resulting from earlier mass loss episodes is unknown, although the presence of dust has been inferred from IR photometry and spectroscopy obtained from previous satellite missions. To date, spectral data have been obtained for V1016 Cyg and V417 Cen in the region 9 – 37 \mum at a resolving power of R = 600. In V1016 Cyg, the broad emission features near 10 and 19 \mum are attributed to silicate dust, and a number of sharp-lined emission features are also present. In contrast, V417 Cen shows no broad emission attributable to dust, and the emission line spectrum is far less pronounced. Future targets include BI Cru, AG Peg, HM Sge, Hen 2-104. These and future data will be analyzed further to provide line identifications and plasma conditions from emission line diagnostics, which we will relate to mechanisms responsible for excitation and ionization processes as evident from other wavelength regions. The analysis of the continuum and broad emission features will help to characterize the dust and its evolutionary history.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.