ISO observations of obscured Asymptotic Giant Branch stars in the Large Magellanic Cloud
Waters, L. B. F. M.; Blommaert, J. A. D. L.; van Loon, J. Th.; Siebenmorgen, R.; Loup, C.; Zijlstra, A. A.; Groenewegen, M. A. T.; Trams, N. R.; Whitelock, P. A.; Heske, A.; Feast, M. W.
Netherlands, United Kingdom, France, South Africa, Germany, Spain
Abstract
We present ISO photometric and spectroscopic observations of a sample of 57 bright Asymptotic Giant Branch stars and red supergiants in the Large Magellanic Cloud, selected on the basis of IRAS colours indicative of high mass-loss rates. PHOT-P and PHOT-C photometry at 12, 25 and 60 mu m and CAM photometry at 12 mu m are used in combination with quasi-simultaneous ground-based near-IR photometry to construct colour-colour diagrams for all stars in our sample. PHOT-S and CAM-CVF spectra in the 3 to 14 mu m region are presented for 23 stars. From the colour-colour diagrams and the spectra, we establish the chemical types of the dust around 49 stars in this sample. Many stars have carbon-rich dust. The most luminous carbon star in the Magellanic Clouds has also a (minor) oxygen-rich component. OH/IR stars have silicate absorption with emission wings. The unique dataset presented here allows a detailed study of a representative sample of thermal-pulsing AGB stars with well-determined luminosities. This paper is based on observations with the Infrared Space Observatory (ISO). ISO is an ESA project with instruments funded by ESA member states (especially the PI countries: France, Germany, The Netherlands and the United Kingdom) and with the participation of ISAS and NASA.