THE MOLECULAR EMISSION-LINE SPECTRUM OF IRC +10216 BETWEEN 330 AND 358 GHZ

We have conducted a spectral line survey of IRC + 10216 using the Calt ech Submillimeter Observatory to an average sensitivity of less than o r similar to 95 mK. A deconvolution algorithm has been used to derive the continuous single-sideband spectrum from 330.2 to 358.1 GHz. A tot al of 56 spectral lines were detected of which 54 have been identified with 8 molecules and a total of 18 isotopomers. The observed lines ar e used to derive column densities and relative abundances for the dete cted species. Within this frequency range the spectral lines detected contribute the majority of the total flux emitted by IRC + 10216. We u se the derived column densities and excitation temperatures to simulat e the molecular line emission (assuming LTE) at frequencies up to 1000 GHz. The observed and simulated flux from line emission is compared t o broadband total flux measurements and to dust emission assuming a po wer-law variation of the dust emissivity. We conclude that significant corrections for the line flux must be made to broadband flux measurem ents of IRC + 10216 at wavelengths longer than approximately 750 mum.