2011ApJ...740...14O

Gas-phase complex organic molecules are commonly detected toward high-mass protostellar hot cores. Detections toward low-mass protostars and outflows are comparatively rare, and a larger sample is the key to investigate how the chemistry responds to its environment. Guided by the prediction that complex organic molecules form in CH₃OH-rich ices and thermally or non-thermally evaporate with CH₃OH, we have identified three sight lines in the Serpens core–SMM1, SMM4, and SMM4-W–which are likely to be rich in complex organics. Using the IRAM 30 m telescope, narrow lines (FWHM of 1-2 km/s) of CH₃CHO and CH₃OCH₃ are detected toward all sources, HCOOCH₃toward SMM1 and SMM4-W, and C₂H₅ OH not at all. Beam-averaged abundances of individual complex organics range between 0.6% and 10% with respect to CH₃ OH when the CH₃ OH rotational temperature is applied. The summed complex organic abundances also vary by an order of magnitude, with the richest chemistry toward the most luminous protostar SMM1. The range of abundances compare well with other beam-averaged observations of low-mass sources. Complex organic abundances are of the same order of magnitude toward low-mass protostars and high-mass hot cores, but HCOOCH₃ is relatively more important toward low-mass protostars. This is consistent with a sequential ice photochemistry, dominated by CHO-containing products at low temperatures and early times.