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 30m 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.
