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

¹ Centre for Astrophysics & Planetary Science, University of Kent, Canterbury, Kent CT2 7NR, UK
² Stockholm Observatory, 133 36 Saltsjöbaden, Sweden
³ Astrophysics Group, The Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 OHE, UK
⁴ Institute for Physical Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel, Switzerland
⁵ Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK
⁶ National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan
⁷ Department of Physics, Queen Mary & Westfield College, University of London, Mile End Road, London E1 4NS, UK

Corresponding author: Glenn J. White, g.j.white@kent.ac.uk

Received: 11 June 2002
Accepted: 22 May 2003

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 ~ 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, SO₂ and CH₃OH and large organic molecules such as (CH₃)₂O, CH₃CN, 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, and 10¹⁴–10 cm respectively.