Dust evolution, a global view: I. Nano-particles, nascence, nitrogen and natural selection . . . joining the dots

TL;DR

This paper explores the role of nano-particles in interstellar chemistry, focusing on their surface chemistry, nitrogen doping effects, and natural selection of nano-structures, using the THEMIS dust evolution model.

Contribution

It introduces a comprehensive framework for understanding nano-particle surface chemistry and nitrogen doping effects in interstellar dust evolution, linking nano-structure properties to chemical processes.

Findings

Nano-particle surface chemistry influences interstellar gas composition.

Nitrogen doping alters nano-particle surface reactions and pre-biotic molecule formation.

Epoxide structures may explain observed gas-phase OH in clouds.

Abstract

The role and importance of nano-particles for interstellar chemistry and beyond is explored within the framework of The Heterogeneous dust Evolution Model at the IaS (THEMIS), focussing on their active surface chemistry (nascence), the effects of nitrogen doping and the natural selection of interesting nano-particle sub-structures. Nano-particle driven chemistry, and in particular the role of intrinsic epoxide-type structures could provide a viable route to the observed gas phase OH in tenuous interstellar clouds en route to becoming molecular clouds. The aromatic-rich moieties present in asphaltenes likely provide a viable model for the structures present within aromatic-rich interstellar carbonaceous grains. The observed doping of such nano-particle structures with nitrogen, if also prevalent in interstellar dust, is likely to have important and observable consequences for surface chemistry and the formation of pre-cursor pre-biotic species.