Sloan et al. 2001, An analysis of O-rich dust ... from the SWS on ISO

An analysis of oxygen-rich dust spectra from the Short Wavelength Spectrometer on the Infrared Space Observatory

G.C. Sloan (Boston College, Cornell), J.H. Goebel (NASA Ames), K.E. Kraemer (Air Force Research Lab, Boston Univ.), S.D. Price (Air Force Research Lab.)

2001, BAAS, 33, 1440

We present initial results of an on-going analysis of the spectra from 160 oxygen-rich dust shells observed by the Short Wavelength Spectrometer (SWS) on the Infrared Space Observatory. The strength of the dust emission feature at 13 µm correlates with the strength of another dust feature centered ~19.5 µm. These features occasionally appear superimposed on the broader emission features from amorphous silicates at 10 and 18 µm, but they appear more often in spectra showing lower-contrast dust emission from amorphous alumina or in some cases from spectra showing little or no other dust emission. Comparison of the spectra with laboratory data of crystalline alumina (alpha-Al₂O₃, which show emission features at 13 and 21 µm, would strengthen the case for crystalline alumina as the carrier of the 13 µm feature if the shift from 21 to 19.5 µm could be explained. We also investigate several additional spectral features. These include the possible emission feature at 7 µm, possible narrow dust features at 12 and 18 µm which may be related to the 13 µm feature, the CO₂ emission bands (at 13.9, 14.9, and 16.2 µm), and the atmospheric absorption bands from CO, SiO, and other molecules in the 2-10 µm spectal region.

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