The following document lists the file abstract/THENNING_HENN_MAG.abs
from catalogue VI/111.
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The knowledge of interstellar grain properties is extremely important for assessing the role of grains in heating/cooling processes, star formation, late stages of stellar evolution, and radiation transfer in the ISM. Studies of the interstellar extinction curves in the Milky Way and the Large and Small Magellanic Clouds have shown significant variations from one galaxy to another, which may be related to the metallicity differences between the galaxies. Magellanic-type dust is interesting because the Clouds have lower abundances of heavy elements and dust than the Milky Way. In this respect, they may resemble galaxies at high redshifts. The Magellanic Clouds are the nearest moderate-sized galaxies to our own galaxy and lie in a direction well out of the galactic plane. Therefore, they are relatively free of foreground extinction and present a unique opportunity for the study of dust properties in external galaxies. In addition, the distances to these external galaxies are with 50 kpc (LMC) and 60 kpc (SMC) very accurately known. Although infrared spectroscopy is the most important tool for determining the dust properties, no such data for a broad wavelength range are available for Magellanic cloud sources. We selected one embedded newly born massive star and one embedded evolved object in each the LMC and SMC. We propose full SWS grating wavelength scans at a reduced spectral resolution from 2.4 to 45 micron to get information on the presence of silicate and ice grains, the existence of small particles and PAHs, and the presence of the 21 and 30 micron feature.