A spectral survey of the orion nebula from 455-507 GHz

Abstract

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 Tmb ∼ 1-3 K. The detected lines are identified as being associated with 30 different molecular species or their isotopemeric variants. The strongest line detected was the J = 4-3 transition of the CO molecule. Apart from abundant rotors such as CO and CS, the spectrum is dominated by SO, SO2 and CH3OH and large organic molecules such as (CH3)2O, CH3 CN, C2H3CN, C2H5CN and HCOOCH3 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, 1014-1017 cm2 respectively.