Interstellar Disparity: N- versus O-bearing Molecules: A Multidisciplinary Perspective across Interstellar Environments

Publications of the Astronomical Society of the Pacific, vol. 138, pp. 106001

Abstract

Abstract Observations of O- and N-bearing molecules reveal systematic chemical differentiation across a wide range of interstellar environments. This pattern is peculiar and its origin likely reflects a combination of physical conditions, chemical pathways, and observational effects rather than a single mechanism. In this paper, we provide a comprehensive overview of the current understanding of the N-bearing and O-bearing species and their relative behaviour in the interstellar medium, integrating results from observations, laboratory experiments, chemical modelling, and theoretical studies. While inspired by discussions at the Lorentz Center workshop held in Leiden in 2025 August, this work goes beyond a summary of the meeting and instead synthesizes the state of the field, highlights key open questions, and outlines future directions. We identify several key observational, experimental, and theoretical challenges that must be addressed to determine the origin of this chemical differentiation.

Authors 3

1. Mathilde Bouvier Aachen

   Leiden University

   Affiliation as printed

   Leiden University

2. Joan Enrique-Romero Aachen

   Leiden University

   Affiliation as printed

   Leiden University

3. M. De Simone

   European Southern Observatory · European Southern Observatory

   Affiliation as printed

   European Southern Observatory