A spectral survey of the Orion Nebula from 455-507 GHz

The results of a submillimetre wavelength spectral line survey between 455.1-507.4 GHz of the Orion-KL hot cloud core are reported. A total of 254 lines were detected to a main beam brightness temperature sensitivity T mb~ 1-3 K. The detected lines are identified as being associated with 30 different molecular species or their isotopomeric variants. The strongest line detected was the J = 4-3 transition of the CO molecule. Apart from abundant diatomic rotors such as CO and CS, the spectrum is dominated by SO, SO 2 and CH 3 OH and large organic molecules such as (CH 3) 2O, CH 3CN, C 2H 5CN, C 2H 5CN and HCOOCH 3 which make up ~72% of the total number of lines; unidentified lines ~13%; and other lines the remaining ~15% of the total. Rotational temperatures and column densities derived using standard rotation diagram analysis techniques were found to range from 70-300 K, and 10^ 14-10 ^17cm ^ 2 respectively.