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ISO Observations of Isolated Herbig AE/BE Stars

Waters, L. B. F. M.; Waelkens, C.; Malfait, K.

We report on SWS and LWS observations of the circumstellar disks of young stars of a few solar masses. The ISO spectra of these objects present a diversity of emission features of carbon-rich and oxygen-rich grains. The similarity of the forsterite spectra observed for Comet Hale-Bopp and the Haebe star HD100546 is particularly striking and provid…

Tentative Detection of Circumstellar CO2 from the AGB Star R Crateris

Ryde, N.; Eriksson, K.; Gustafsson, B. +2 more

We report on and discuss the detection of an emission feature at 14.98 µm from the oxygen-rich, semi-regularly pulsating Asymptotic Giant Branch star R Crateris, a feature which we suggest to be due to the <Stack> ₀ ¹ </Stack> Q-branch of circumstellar CO2. We also suggest a reasonable excitation mechanism, which …

Extreme Infrared Stars Discovered in Magellanic Cloud Globular Clusters

Glass, I. S.; Sauvage, M.; Onaka, T. +3 more

We report preliminary results of our systematic survey for infrared stars in the globular clusters of the Magellanic Clouds. In the course of an ISOCAM survey for AGB stars in the intermediate-age clusters, we have discovered extremely red AGB stars in NGC 419 and NGC 1978. From their colours and luminosities, they are thought to be experiencing i…

Dust in LBV Nebulae

Waters, L. B. F. M.; Morris, P. W.; Lamers, H. J. G. L. M. +2 more

Infrared Observations of the Transition from Chaotic to Crystalline Silicates via Thermal Annealing in the Laboratory

Hallenbeck, S.; Nuth, J.

ISO-SWS Observations of Weak Bands of Trace Components of Ices Towards the Young Stellar Object W 33A

van Dishoeck, E. F.; Whittet, D. C. B.; Schutte, W. A. +3 more

ISO-SWS observations of the highly obscured young stellar object W 33A reveal two broad absorption features centered at 7.24 and 7.40 µm. The position and width of these features indicates that they are due to the XH bending mode (X = C, N, or O) of molecules in the solid state. Comparison to interstellar ice analogs shows that the 7.24 µm band ca…

PAH's and Crystalline Silicates in Planetary Nebulae

Beintema, D. A.

An overview is given of the PAH and crystalline silicate emissions seen in the SWS guaranteed-time programme on planetary nebulae. Of the 9 objects on which good continuum measurements were obtained above 29 µm, 7 show evidence of olivine emission at 33.5 µm. PAH emission is seen in 5 of these objects, 3 objects show both PAH's and olivines. The p…

Molecules in AGB Stars Observed with ISO

Cernicharo, J.

I present in this review the recent results obtained with ISO concerning gas phase molecules in evolved stars. The near, medium and far-infrared spectrum of C-rich and O-rich stars can provide a very important information on the molecular content of these objects. Detailed models for the envelopes of AGB stars are also presented. I also report the…

ISO Observations of Wolf-Rayet Dust Shells

Morris, P. W.; van der Hucht, K. A.; Williams, P. M.

Observations of circumstellar dust clouds of Wolf-Rayet stars made with the Short Wavelength Spectrometer on ISO reveal a subtle variety of spectral energy distributions not evident from ground-based observations. The modelling of these using the radiative transfer code "Dusty" by Ivezić, Nenkova & Elitzur is reported. The results are used to …

ISO-SWS Observations of the Time Variability of Oxygen-righ Mira Variables

Izumiura, H.; Onaka, T.; Tanabé, T. +3 more

We present the first observation of variation of the infrared spectrum of circumstellar dust emission around an oxygen-rich Mira variable star, Z Cyg, over an entire light variation cycle, based on the periodic SWS01 observations. The 10 µm and 20 µm ‘silicate features’ become stronger relative to the photospheric emission at maximum that at minim…