Fullerenes, the carbon molecules with 60 and 70 atoms, were recently detected in a series of planetary nebulae, in protoplanetary nebulae and in other astrophysical objects. The detection and the quantitative determination of these molecules was made possible by the measurement of their reference infrared spectra and the relative molar extinction

We construct a detailed model for the IR dust emission from the PN IC 418. We succeed to reproduce the emission from 2 to 200 μm. We can determine the amount of emitting dust as well as its composition, and compare to the depletion of elements determined for the photoionized region.

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Optical and near-infrared variability is a well-known property of young stellar objects. However, a growing number of recent studies claim that a considerable fraction of them also exhibit mid-infrared flux changes. With the aim of studying and interpreting variability on a decadal timescale, here we present a mid-infrared spectral atlas containing

We report on a program of spectroscopic observations of gravitationally lensed QSOs with multiple images. We seek to establish whether microlensing is occurring in each QSO image using only single-epoch observations. We calculate flux ratios for the cores of emission lines in image pairs to set a baseline for no microlensing. The offset of the