Infrared astronomy

Progress in the understanding of the interaction of stars with the interstellar medium brought about by observations in the infrared spectral range, between 1 μm and 1 mm wavelength is summarised. This includes direct observations of star formation (and even possibly of planetary formation) from clouds of dust and molecular gas, and also of material returning from the outer atmospheres of luminous stars into interstellar space. Extragalactic sources now observed to emit predominantly in the infrared include the most luminous objects known, while the all-pervading millimetre and submillimetre background radiation provides the best method of measuring the parameters of primaeval Universe. (author)