It's COMplicated: Disentangling the formation pathways of complex organic molecules from molecular clouds to comets.
Complex organic molecules (COMs), the chemical building blocks from which pre-biotic molecules can arise, must form on icy dust grains within cold molecular clouds, where their gas-phase sublimation products have been extensively studied with millimeter telescopes."Non-energetically" processed cloud COMs may be thermally and energetically reprocessed within protostellar envelopes, either further increasing their complexity or potentially destroying them before they enter the comet-forming regions of protoplanetary disks. However, to date no COMs more complex than methanol have been conclusively detected in the solid state.We propose to test whether energetic reprocessing COMs during the protostellar stage of star formation substantially enhances the ice chemical complexity over that of cold molecular cores by obtaining R~2700-3200 spectra from 3-15um along six lines of sight to ice-rich regions characterized by non-energetic, thermal, and energetic ice processing. These spectra will reveal and disentangle overlapping signatures of >4 specific COM species (acetaldehyde, ethanol, dimethyl ether, and methyl formate), which are suggested by previous 5-sigma absorption features at 3-7% of the continuum near 7.2um with Spitzer, guaranteeing a robust detection of the separate features. If the complexity of COMs is already high enough within our non-energetic targets, then it means that every star system formed from those clouds could come pre-seeded with the partially assembled ingredients for life. If we still detect COMs in the highly energetically processed targets, then we can gauge how much and what variety of species survive the journey from cloud to comet-forming disk.
JWST Proposal. Cycle 1
- Pub Date:
- March 2021