相关论文: Chemistry in Evaporating Ices: Unexplored Territor…
Major components of ices on interstellar grains in molecular clouds - water and carbon oxides - occur at various optical depths. This implies that selective desorption mechanisms are at work. An astrochemical model of a contracting low-mass…
We propose a new model for treating solid-phase photoprocesses in interstellar ice analogues. In this approach, photoionization and photoexcitation are included in more detail, and the production of electronically-excited (suprathermal)…
Three-body recombination is a prime example of the fundamental interaction between three particles. Due to the complexity of this process it has resisted a comprehensive description. Experimental investigations have mainly focussed on the…
The interstellar medium is characterized by a rich and diverse chemistry. Many of its complex organic molecules are proposed to form through radical chemistry in icy grain mantles. Radicals form readily when interstellar ices (composed of…
In the past decade, there has been a significant shift in astrochemistry with a renewed focus on the role of non-thermal processes on the molecular interstellar medium, in particular energetic particles (such as cosmic ray particles and…
Isolated dense molecular cores are investigated to study the onset of complex organic molecule formation in interstellar ice. Sampling three cores with ongoing formation of low-mass stars (B59, B335, and L483) and one starless core (L694-2)…
Understanding gas-grain chemistry of deuterium in star-forming objects may help to explain their history and present state. We aim to clarify how processes in ices affect the deuterium fractionation. In this regard, we investigate a…
A new, more comprehensive model of gas-grain chemistry in hot molecular cores is presented, in which nondiffusive reaction processes on dust-grain surfaces and in ice mantles are implemented alongside traditional diffusive surface/bulk-ice…
We have made self-consistent models of the density and temperature profiles of the gas and dust surrounding embedded luminous objects using a detailed radiative transfer model together with observations of the spectral energy distribution…
Our goal is to take an inventory of complex molecules in three well-known high-mass protostars for which disks or toroids have been claimed and to study the similarities and differences with a sample of massive YSOs without evidence of such…
The results of experiments on the formation of molecular hydrogen on low density and high density amorphous ice surfaces are analyzed using a rate equation model. The activation energy barriers for the relevant diffusion and desorption…
To explain grain growth and destruction in warm media, ice mantle formation and sublimation in cold media, and gas line emission spectroscopy, astrochemical models must mimic the gas--solid abundance ratio. Ice-sublimation mechanisms…
Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of T_e^-9/2. We measure three-body recombination in an ultracold neutral xenon plasma by…
Young massive star-forming regions are known to produce hot molecular gas cores (HMCs) with a rich chemistry. While this chemistry is interesting in itself, it also allows to investigate important physical parameters. I will present recent…
Gas-phase complex organic molecules have been detected toward a range of high- and low-mass star-forming regions at abundances which cannot be explained by any known gas-phase chemistry. Recent laboratory experiments show that UV…
We consider three-body recombination into deep dimers in a mass-imbalanced two-component atomic gas. We use an optical model where a phenomenological imaginary potential is added to the lowest adiabatic hyper-spherical potential. The…
Context. The presence of dust in the interstellar medium has profound consequences on the chemical composition of regions where stars are forming. Recent observations show that many species formed onto dust are populating the gas phase,…
CO2 ices are known to exist in different astrophysical environments. In spite of this, its physical properties (structure, density, refractive index) have not been as widely studied as those of water ice. It would be of great value to study…
Thermal annealing of interstellar ices takes place in several stages of star formation. Knowledge of this process comes from a combination of astronomical observations and laboratory simulations under astrophysically relevant conditions.…
Water ice is abundant both astrophysically, for example in molecular clouds, and in planetary systems. The Kuiper belt objects, many satellites of the outer solar system, the nuclei of comets and some planetary rings are all known to be…