Related papers: One-dimensional and time-dependent modelling of co…
We compute numerical simulations of spherical collapse triggered by a slow increase in external pressure. We compare isothermal models to models including cooling with a simple but self-consistent treatment of the coupling between gas,…
Hot molecular cores (HMCs), the cradles of massive stars, are the most chemically rich sources in the Galaxy. The typical masses of these cores (few hundreds of solar masses) make them the most important reservoirs of complex organic…
Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial…
Icy interstellar dust grains are a source of complex organic molecule (COM) production, although their formation mechanisms are debated. Laboratory experiments show that atomic C deposited onto interstellar ice analogs can react with…
Abridged: We detail and benchmark two sophisticated chemical models developed by the Heidelberg and Bordeaux astrochemistry groups. The main goal of this study is to elaborate on a few well-described tests for state-of-the-art astrochemical…
The object W33 is a giant molecular cloud that contains star forming regions at various evolutionary stages from quiescent clumps to developed H II regions. Since its star forming regions are located at the same distance and the primary…
Complex organic molecules (COMs) have been detected in the gas-phase in cold and lightless molecular cores. Recent solid-state laboratory experiments have provided strong evidence that COMs can be formed on icy grains through…
Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of resulting star and planetary systems. Here we study the role of pressure, parameterized via ambient clump mass surface…
To understand the chemistry of sulphur (S) in the interstellar medium, models need to be tested by observations of S-bearing molecules in different physical conditions. We analyse observations obtained with the IRAM 30m telescope towards 15…
This paper presents a systematic survey of the deuterated and 13C isotopologues of a variety of oxygen-bearing complex organic molecules on Solar System scales toward the protostar IRAS 16293-2422B. We use the data from an unbiased…
Complex organic molecules (COM) are detected in many sources in the warm inner regions of envelopes surrounding deeply embedded protostars. Exactly how these COM form remains an open question. This study aims to constrain the formation of…
No statistical study of COMs toward a large sample of high-mass protostars with ALMA has been carried out so far. We aim to study six N-bearing species: CH$_3$CN, HNCO, NH$_2$CHO, C$_2$H$_5$CN, C$_2$H$_3$CN and CH$_3$NH$_2$ in a large…
Complex organic molecules (COMs) have been detected ubiquitously in protostellar systems. However, at shorter wavelengths (~0.8mm) it is more difficult to detect larger molecules than at longer wavelengths (~3mm) because of the increase of…
Cosmic rays (CRs) are important drivers for molecular chemistry in star-forming regions, and laboratory experiments have shown that CRs can stimulate the release of complex organic molecules (COMs) such as methanol. Observationally, this…
We study the formation and evolution of several molecules in a collapsing interstellar cloud using a reasonably large reaction network containing more then four hundred atomic and molecular species. We employ a time dependent, spherically…
The chemical changes of high-mass star-forming regions provide a potential method for classifying their evolutionary stages and, ultimately, ages. In this study, we search for correlations between molecular abundances and the evolutionary…
The presence of complex organic molecules (COMs) in the interstellar medium (ISM) is of great interest since it may link to the origin and prevalence of life in the universe. Aiming to investigate the occurrence of COMs and their possible…
Hot core molecules should be detectable in external active galaxies out to high redshift. We present here a detailed study of the chemistry of star-forming regions under physical conditions that differ significantly from those likely to be…
Large interstellar organic molecules are potential precursors of prebiotic molecules. Their formation pathways and chemical relationships with one another and simpler molecules are therefore of great interest. In this paper, we address the…
According to traditional gas-phase chemical models, O2 should be abundant in molecular clouds, but until recently, attempts to detect interstellar O2 line emission with ground- and space-based observatories have failed. Following the…