Heteronuclear diatomics in diffuse and translucent clouds

TL;DR

This paper reviews recent observational advances in detecting heteronuclear diatomic molecules in diffuse and translucent interstellar clouds, highlighting their role in understanding interstellar chemistry and physical conditions.

Contribution

It provides a comprehensive review of astronomical observations of heteronuclear diatomics and discusses their spectral features and relation to diffuse interstellar bands.

Findings

Detection of vibrational-rotational spectra in high-quality spectra

Relations between column densities of molecules and DIB intensities

Recent observational data on molecular features in spectra of OB stars

Abstract

Diffuse and translucent molecular clouds fill a vast majority of the interstellar space in the galactic disk being thus the most typical objects of the Interstellar Medium (ISM). Recent advances in observational techniques of modern optical and ultraviolet spectroscopy led to detection of many features of atomic and molecular origin in spectra of such clouds. Molecular spectra of heteronuclear diatomic molecules, ie. OH, OH+, CH CH+, CN, NH, CO play an important role in understanding chemistry and physical conditions in environments they do populate. A historical review of astronomical observations of interstellar molecules is presented. Recent results based on visual and ultraviolet observations of molecular features in spectra of reddened, early type OB-stars are presented and discussed. Appearance of vibrational-rotational spectra with observed transitions based on high-quality spectra, are also presented. Relations between column densities of heteronuclear diatomics (based on the recommended oscillator strengths) and intensities of diffuse interstellar bands (DIBs) are also presented and discussed.