The Chemistry of the Early Universe

TL;DR

This paper reviews the chemical processes in the early Universe, emphasizing how molecular hydrogen influences star and galaxy formation, and discusses the chemical evolution during gas collapse leading to star formation.

Contribution

It provides a comprehensive overview of the chemical evolution in the early Universe, highlighting the role of molecular hydrogen and the processes during gas collapse.

Findings

Chemical complexity possible without elements heavier than lithium

Molecular hydrogen's key role in star and galaxy formation

Chemical processes during gas collapse influence star formation outcomes

Abstract

The chemistry of the early Universe is a fascinating field of study. Even in the absence of any elements heavier than lithium, a surprising degree of chemical complexity proves to be possible, giving the topic considerable interest in its own right. In addition, the fact that molecular hydrogen plays a key role in the formation of the first stars and galaxies means that if we want to understand the formation of these objects, we must first develop a good understanding of the chemical evolution of the gas. In this review, I first give a brief introduction to the chemistry occurring in the gas prior to the formation of the first stars and galaxies, and then go on to discuss in more detail the main chemical processes occurring during the gravitational collapse of gas from intergalactic to protostellar densities, and how these processes influence the final outcome of the collapse.