Experimental evidence of water formation on interstellar dust grains

TL;DR

This study provides the first experimental evidence that water can form on icy dust grains in interstellar space, supporting theories about water's cosmic origins and its role in prebiotic chemistry.

Contribution

It demonstrates water synthesis on interstellar dust analogs at 10 K, revealing the active role of water ice in forming complex organic molecules.

Findings

Water formation observed on icy dust analogs at 10 K

Production of HDO and DO indicates active water synthesis

Water ice acts as a matrix for complex organic chemistry

Abstract

The synthesis of water is one necessary step in the origin and development of life. It is believed that pristine water is formed and grows on the surface of icy dust grains in dark interstellar clouds. Until now, there has been no experimental evidence whether this scenario is feasible or not. We present here the first experimental evidence of water synthesis under interstellar conditions. After D and O deposition on a water ice substrate (HO) held at 10 K, we observe production of HDO and DO. The water substrate itself has an active role in water formation, which appears to be more complicated than previously thought. Amorphous water ice layers are the matrices where complex organic prebiotic species may be synthesized. This experiment opens up the field of a little explored complex chemistry that could occur on interstellar dust grains, believed to be the site of key processes leading to the molecular diversity and complexity observed in our universe.