Pascale Ehrenfreund

Leiden

COSMIC DUST: NEW RESULTS FROM THE INFRARED SPACE OBSERVATORY ISO

Besides abundant H and He, 120 interstellar and circumstellar gas phase
molecules are currently identified along with a small fraction of interstellar
dust composed of a mixture of materials from various sources. The Infrared
Space Observatory ISO has provided extraordinary results concerning the nature
of cosmic dust particles. ISO allowed a new definition of the composition of
interstellar ices and thermal processing in the protostellar vicinity. ISO
observations of bright star-forming regions obtained with the Short Wavelength
Spectrometer (SWS) showed the ubiquitous presence of abundant CO2 in space and
allowed to derive accurate abundances for several ice species. ISO results of
interstellar gas and dust in comparison with laboratory results and
theoretical models allowed to determine the line of sight conditions such as
gas/grain interactions, temperature and irradiation toward star-forming
regions. A comparison of interstellar and cometary dust using recent ISO data
has revealed important similarities and provides important constraints on the
formation of the Solar System and the early evolution on Earth.