Interstellar nanodiamonds: the carriers of mid-infrared emission bands?

TL;DR

This paper explores the potential of interstellar nanodiamonds to produce mid-infrared emission bands through surface-related processes, suggesting they could explain certain unidentified astronomical IR features.

Contribution

It demonstrates that nanodiamonds can be stochastically heated in space, producing IR emission bands linked to their surface structures, a novel explanation for observed mid-infrared features.

Findings

Nanodiamonds can reach temperatures up to 1000 K in space.

Surface structures of nanodiamonds produce discrete IR emission bands.

Nanodiamonds may significantly contribute to 3-15 micron IR emission bands.

Abstract

In this paper we pursue the natural consequences of the structure of nanodiamonds and their surface relaxation and reconstruction to surfaces exhibiting sp2 carbon atoms. We show that in the interstellar radiation field nanodiamonds can be stochastically heated to temperatures as high as 1000 K and give rise to discrete emission bands associated with the surface structures. We therefore speculate that nanodiamonds can make a significant contribution towards the 3-15 micron unidentified mid-infrared emission bands.