FAR-INFRARED SPECTROSCOPY OF NUCLEARLY PROCESSED MATERIAL IN YOUNG SUPERNOVA REMNANTS.

> in this proposal, more time is being requested for dpequign.ism_iii guaranteedtime lws grating spectra have shown atomic finestructure line emission in a number of young supernova remnants (snr) in the galaxy and the magellanic clouds. continuum dust emission was also detected. this exploratory phase has revealed at least two remnants, cas a and g320.41.2, with broad fir o iii and o i emission, see figure 1. this emission is not correlated with optical emission, suggesting that a new gas phase is being detected in snrs. these broad lines are thought as a signature of expanding, highly processed, possibly very cool, ejecta from supernovae. complementary observations with iso are essential in two directions: 1/ mapping with the lws in o iii and o i in order to delineate the extension, velocity field, and total intensity of the emission in some sources. 2/ spectroscopy with the sws at selected positions to get a more comprehensive description of the chemical composition and physical conditions in the ejecta from finestructure lines. some targets of the gt lws programme on snrs have not yet been observed but we anticipate either from experience gained with the first observations or from detailed modelling, that at least two important targets will absolutely need follow up with sws observations: g292.0+1.8, an orich galactic snr, and the crab nebula. expected outputs include (1) a characterization of a new gas phase in snrs, (2) an original determination of the mass of nuclearlyprocessed material in young snrs, and (3) the relative abundances of the elements synthesized in the supernovae. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]