Astrochemistry

Overview Of Complex Organic Molecule Observations In Protostellar Systems

By Keith Cowing
Status Report
astro-ph.GA
August 22, 2025
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Overview Of Complex Organic Molecule Observations In Protostellar Systems
Cartoon showing different components of a protostellar system. The ices are thought to form in layers with different molecules at different temperatures and densities (see review by Herbst and van Dishoeck 2009). Although JWST has detected COMs in ices, it is still under debate in which layer and at what stage of star formation they form. The icy dust grains and the gas in the envelope gets accreted onto the disk and eventually onto the planetesimals or comets that may be forming there. — astro-ph.GA

Complex organic molecules (COMs) have been detected abundantly at various stages of star formation, particularly in the warm protostellar phase.

The progress in gas-phase measurements has been accelerated by the advent of the Atacama Large Millimeter/submillimeter Array and in ice measurements by the James Webb Space Telescope.

Particularly, the community has moved from single-source studies of COMs to statistical analyses because of these powerful instruments. In this article, I review surveys that consider COMs in the gas and ice. The two takeaways from this review include;

  1. Gas-phase abundance ratios for some COMs show a small difference across many objects and the ice abundance ratios show similar or higher values to the gas, both pointing to the importance of ice chemistry in COM formation,
  2. Some COM ratios show larger differences across many objects which could be due to either chemical or physical effects, thus both factors need to be considered when interpreting the data.

P. Nazari

Comments: Invited submission to a special astrochemistry issue in the Life Sciences in Space Research journal, 22 pages, 5 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2508.15771 [astro-ph.GA] (or arXiv:2508.15771v1 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2508.15771
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Submission history
From: Pooneh Nazari
[v1] Thu, 21 Aug 2025 17:59:29 UTC (1,160 KB)
https://arxiv.org/abs/2508.15771
Astrobiology,

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