The detection of ethanol in W 51M

The authors have searched for 3 rotational transitions of ethanol, CH3CH2OH, toward W51 M and Orion-KL, detecting it in the former source. The analysis indicates that, in W51 M, the ethanol emission arises in a warm gas probably similar to that detected previously in methanol and dimethyl ether. The abundances of all 3 molecules are much higher than predicted by gas phase chemistry and the authors suggest a novel mechanism for the formation of such complex species in grain surface reactions. This mechanism appears able to account for, in a qualitative manner, the overabundance of dimethyl ether compared to ethanol in Orion-KL and suggests that branched chain hydrocarbon molecules might be abundant in hot dense regions.