# Observations of chemical differentiation in clumpy molecular clouds

## TL;DR

This study maps multiple dense molecular clouds revealing widespread chemical differentiation, which correlates with their evolutionary stages and physical properties, providing insights into the origin of clumpy structures in dense clouds.

## Contribution

It presents extensive molecular line maps of several clouds, demonstrating systematic chemical differentiation linked to cloud evolution, and compares observations with chemical models.

## Key findings

- Chemical differentiation is prevalent in all observed clouds.
- Differentiation correlates with the clouds' evolutionary states.
- Observations align with simple chemical model predictions.

## Abstract

We have extensively mapped a sample of dense molecular clouds (L1512, TMC-1C, L1262, Per 7, L1389, L1251E) in lines of HC3N, CH3OH, SO and C^{18}O. We demonstrate that a high degree of chemical differentiation is present in all of the observed clouds. We analyse the molecular maps for each cloud, demonstrating a systematic chemical differentiation across the sample, which we relate to the evolutionary state of the cloud. We relate our observations to the cloud physical, kinematical and evolutionary properties, and also compare them to the predictions of simple chemical models. The implications of this work for understanding the origin of the clumpy structures and chemical differentiation observed in dense clouds are discussed.