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

TL;DR

This pilot survey investigates the prevalence and abundance of complex organic molecules in low-mass star-forming regions, revealing that moderate COM abundances are common during early star formation stages.

Contribution

First systematic survey of COM lines toward low-mass YSOs combining new and previous data to assess COM frequency and abundance distributions.

Findings

Over 50% of YSOs show COM detection or upper limits of 1-10% relative to CH3OH.

COMs are commonly present at moderate abundances in early low-mass star formation.

Detection of multiple COMs in a subset of embedded YSOs.

Abstract

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.