TMC-1: probing the onset of chemical complexity in space

TL;DR

This paper reviews recent advances in understanding the chemical complexity of TMC-1, highlighting observational progress from the QUIJOTE survey and discussing challenges in chemical modeling, especially regarding PAH origins.

Contribution

It provides an overview of the QUIJOTE line survey, summarizes observational findings, and discusses the limitations of current chemical models for TMC-1.

Findings

Number of molecules in TMC-1 has more than doubled.

The QUIJOTE survey covers 31-50 GHz with the Yebes 40m radiotelescope.

Current models struggle to explain the origin of PAHs.

Abstract

In recent years, the obsessive interest in the observation of TMC-1 has brought a boost in our knowledge of the chemistry of cold dark clouds. The number of molecules detected in this particular cloud has been more than doubled. Two observational programmes, GOTHAM and QUIJOTE, are responsible for this spectacular achievement. Here we provide an overall view of QUIJOTE, which is a line survey carried out in the Q band (31-50 GHz) with the Yebes 40m radiotelescope, summarize the actual observational status of TMC-1, and discuss the chemistry of this remarkable source. We highlight the successes and failures of state-of-the-art chemical models to describe its chemical composition, with a particular emphasis on the origin of PAHs, which is yet far from being understood.