# Interstellar Glycolaldehyde, Methyl Formate, and Acetic Acid I: A Bi-modal Abundance Pattern in Star Forming Regions

## TL;DR

This study investigates the relative abundances of glycolaldehyde, methyl formate, and acetic acid in star-forming regions, revealing a bi-modal distribution for two isomers that may shed light on chemical processes in protostellar environments.

## Contribution

It presents the first observation of a bi-modal abundance pattern in glycolaldehyde and methyl formate across multiple star-forming regions, suggesting a common influencing parameter.

## Key findings

- Bi-modal distribution of glycolaldehyde and methyl formate abundances.
- No bi-modal pattern observed for acetic acid.
- Implication of a common parameter affecting glycolaldehyde formation.

## Abstract

The relative column densities of the structural isomers methyl formate, glycolaldehyde, and acetic acid are derived for a dozen positions towards the massive star-forming regions MM1 and MM2 in the NGC 6334I complex, which are separated by $\sim$4000 AU. Relative column densities of these molecules are also gathered from the literature for 13 other star-forming regions. In this combined dataset, a clear bi-modal distribution is observed in the relative column densities of glycolaldehyde and methyl formate. No such distribution is evident with acetic acid. The two trends are comprised of star-forming regions with a variety of masses, suggesting that there must be some other common parameter that is heavily impacting the formation of glycolaldehyde. This is indicative of some demonstrable differentiation in these cores; studying the abundances of these isomers may provide a clue as to the integral chemical processes ongoing in a variety of protostellar environments.