We present observations of interstellar acetone (CH_3_COCH_3_) detected in broadband line surveys in the 1.3mm band from the Caltech Submillimeter Observatory (CSO). The observations were conducted toward three massive star-forming regions: GAL31.41+0.31, GAL034.3+00.2, and GAL10.47+00.03. Numerous acetone lines were detected in these three sources. The results were analyzed using the assumption of local thermodynamic equilibrium. These results rigorously confirm the previous reports of acetone detections in GAL31.41+0.31 and GAL10.47+00.03, and add a new acetone detection in GAL034.3+00.2. Source-averaged column densities for acetone were determined to be 1.1(6)x10^16^cm^-2^ for GAL31.41+0.31, 6.4(3)x10^16^cm^-2^ for GAL10.47+00.03, and 1.3(3)x10^15^cm^-2^ for GAL034.3+00.2. The rotational temperatures of acetone in these three sources range from 49 to 132K, which suggests a complicated formation mechanism for interstellar acetone.

Cone search capability for table J/ApJ/849/139/regions (Observational parameters and beam-averaged and source-averaged fit results of acetone lines using the GOBASIC program (Rad+ 2016, J/A+A/585/A23) (tables 1 and 3))