Acetaldehyde in star-forming regions Original Research Article

Observations of acetaldehyde (CH3CHO) in a survey of nine star-forming regions are presented. Emission is clearly detected from both the A and E symmetry states in the 404–303 and 505–404 transitions. Both the range of the measured CH3CHO column densities (∼4×1012–1014 cm−2), and the derived fractional abundances, are in good agreement with other studies. The origin of interstellar CH3CHO and its structural isomers is discussed in the light of this work and previous observations. It is concluded that specific grain-surface chemistries are responsible for the production of the C2H4O compounds and other related organic molecules. Possible observational tests to distinguish between different surface pathways are suggested.