Evolution of dispersion in the cosmic deuterium abundance

TL;DR

This paper models the cosmic evolution of deuterium in the interstellar medium, showing how galaxy formation impacts its abundance and dispersion, and proposes a method to estimate primordial deuterium levels.

Contribution

It introduces realistic galaxy evolution models that match observed deuterium and metal abundances and predicts a tight correlation useful for measuring primordial deuterium.

Findings

Models align with observed deuterium and metal abundances.

Low star formation efficiency explains low astration factor.

Predicted correlation between deuterium and metal abundances.

Abstract

Deuterium is created during Big Bang Nucleosynthesis, and, in contrast to the other light stable nuclei, can only be destroyed thereafter by fusion in stellar interiors. In this paper we study the cosmic evolution of the deuterium abundance in the interstellar medium and its dispersion using realistic galaxy evolution models. We find that models that reproduce the observed metal abundance are compatible with observations of the deuterium abundance in the local ISM and z ~ 3 absorption line systems. In particular, we reproduce the low astration factor which we attribute to a low global star formation efficiency. We calculate the dispersion in deuterium abundance arising from different structure formation histories in different parts of the Universe. Our model also predicts an extremely tight correlation between deuterium and metal abundances which could be used to measure the primordial deuterium abundance.