# Two dimensional ice mapping of molecular cores

## TL;DR

This study maps the distribution of water, carbon dioxide, and carbon monoxide ices in multiple molecular cores, revealing complex spatial relationships that challenge traditional models and offering new insights into small-scale chemical diversity before star formation.

## Contribution

It provides the first combined solid-gas maps of a single molecular species and demonstrates the use of component analysis to explore small-scale chemical variations.

## Key findings

- Ice maps challenge the assumption that denser regions have more ice.
- First combined solid-gas maps of CO ice and gas phase C$^{18}$O.
- Solid phase molecules are effective tracers of chemical diversity.

## Abstract

We present maps of the column densities of H$_2$O, CO$_2$, and CO ices towards the molecular cores B~35A, DC~274.2-00.4, BHR~59, and DC~300.7-01.0. These ice maps, probing spatial distances in molecular cores as low as 2200~AU, challenge the traditional hypothesis that the denser the region observed, the more ice is present, providing evidence that the relationships between solid molecular species are more varied than the generic picture we often adopt to model gas-grain chemical processes and explain feedback between solid phase processes and gas phase abundances. We present the first combined solid-gas maps of a single molecular species, based upon observations of both CO ice and gas phase C$^{18}$O towards B~35A, a star-forming dense core in Orion. We conclude that molecular species in the solid phase are powerful tracers of "small scale" chemical diversity, prior to the onset of star formation. With a component analysis approach, we can probe the solid phase chemistry of a region at a level of detail greater than that provided by statistical analyses or generic conclusions drawn from single pointing line-of-sight observations alone.