Abstract

The earliest stages of star- and planet formation are obscured by tens to hundreds of magnitudes of extinction. Observations of the gas and dust at long wavelengths often provide the only way to obtain information on the physical and chemical processes that occur deep inside these regions. In this talk, an overview of Spitzer, VLT , and JCMT spectroscopic observations of ices, silicates, PAHs and hot gases will be given. Spitzer has opened up the possibility to obtain high quality mid-infrared spectra for large numbers of low-mass protostars and disks around solar-mass pre-main sequence stars for the first time, whereas VLT -CRIRES provide complementary high spatial and spectral resolution data down to 1 AU. The results will be analyzed using models of evolving protostellar envelopes and disks, including transitional disks with inner holes and gaps in which planets may have formed. The diagnostic values of the various lines and bands will be emphasized, and the importance of laboratory data to interpret them will be illustrated. Initial Herschel Space Observatory results will be presented. The prospects for future facilities, in particular Herschel, the James Webb Space Telescope and the Atacama Large Millimeter Array, will be discussed.