Complex organic molecules during low-mass star formation: Pilot survey results

Complex organic molecules (COMs) are known to be abundant toward some low-mass young stellar objects (YSOs), but how these detections relate to typical COM abundance are not yet understood. We aim to constrain the frequency distribution of COMs during low-mass star formation, beginning with this pilot survey of COM lines toward six embedded YSOs using the IRAM 30 m Telescope. The sample was selected from the Spitzer c2d ice sample and covers a range of ice abundances. We detect multiple COMs, including CH₃CN, toward two of the YSOs, and tentatively toward a third. Abundances with respect to CH₃OH vary between 0.7% and 10%. This sample is combined with previous COM observations and upper limits to obtain a frequency distributions of CH₃CN, HCOOCH₃, CH₃OCH₃, and CH₃CHO. We find that for all molecules more than 50% of the sample have detections or upper limits of 1%-10% with respect to CH₃OH. Moderate abundances of COMs thus appear common during the early stages of low-mass star formation. A larger sample is required, however, to quantify the COM distributions, as well as to constrain the origins of observed variations across the sample.