相关论文: Desorption From Interstellar Ices

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…

Absorption of ultraviolet radiation by water ice coating interstellar grains can lead to dissociation and desorption of the ice molecules. These processes are thought to be important in the gas-grain chemistry in molecular clouds and…

The standard model of cosmic ray heating-induced desorption of interstellar ices is based on a continuous representation of the sporadic desorption of ice mantle components from classical (0.1 micron) dust grains. This has been re-evaluated…

Physical conditions in dense and cold regions of interstellar clouds favour the formation of ice mantles on the surfaces of interstellar grains. It is predicted that most of the gaseous species heavier than H2 or He will adsorb onto the…

We compute the desorption rate of icy mantles on dust grains as a function of the size and composition of both the grain and the mantle. We combine existing models of cosmic ray (CR) related desorption phenomena with a model of CR transport…

Water (H2O) ice is an important solid constituent of many astrophysical environments. To comprehend the role of such ices in the chemistry and evolution of dense molecular clouds and comets, it is necessary to understand the freeze-out,…

Molecular clouds are the cold regions of the Milky Way where stars form. They are enriched by rather complex molecules. Many of these molecules are believed to be synthesized on the icy surfaces of the interstellar submicron-sized dust…

A longstanding problem in astrochemistry is how molecules can be maintained in the gas phase in dense inter- and circumstellar regions. Photodesorption is a non-thermal desorption mechanism, which may explain the small amounts of observed…

In molecular clouds at temperatures as low as 10 K, all species except hydrogen and helium should be locked in the heterogeneous ice on dust grain surfaces. Nevertheless, astronomical observations have detected over 150 different species in…

A new experimental set-up INterStellar Ice-Dust Experiment (INSIDE), was designed for studying cosmic grain analogues represented by ice-coated carbon- and silicate-based dust grains. In the new instrument, we can simulate physical and…

Under cold conditions in dense cores, gas-phase molecules and atoms are depleted from the gas-phase to the surface of interstellar grains. Considering the time scales and physical conditions within these cores, a portion of these molecules…

In regions where stars form, variations in density and temperature can cause gas to freeze-out onto dust grains forming ice mantles, which influences the chemical composition of a cloud. The aim of this paper is to understand in detail the…

Context. Interstellar ice is the main form of metal species in dark molecular clouds. Experiments and observations have shown that the ice is significantly processed after the freeze-out of molecules onto grains. The processing is caused by…

Context. Interstellar surface chemistry is a complex process that occurs in icy layers accumulated onto grains of different sizes. Efficiency of surface processes often depends on the immediate environment of adsorbed molecules. Aims. We…

UV ice photodesorption is an important non-thermal desorption pathway in many interstellar environments that has been invoked to explain observations of cold molecules in disks, clouds and cloud cores. Systematic laboratory studies of the…

Water is usually the main component of ice mantles, which cover the cores of dust grains in cold portions of dense interstellar clouds. When molecular hydrogen is adsorbed onto an icy mantle through physisorption, a common assumption in…

At the high densities and low temperatures found in star forming regions, all molecules other than H2 should stick on dust grains on timescales shorter than the cloud lifetimes. Yet these clouds are detected in the millimeter lines of…

Aims: The gas-phase abundance of methanol in dark quiescent cores in the interstellar medium cannot be explained by gas-phase chemistry. In fact, the only possible synthesis of this species appears to be production on the surfaces of dust…

Non-thermal desorption of ices on interstellar grains is required to explain observations of molecules that are not synthesized efficiently in the gas phase in cold dense clouds. Perhaps the most important non-thermal desorption mechanism…

In the interstellar medium (ISM), the formation of complex organic molecules (COMs) is largely facilitated by surface reactions. However, in cold dark clouds, thermal desorption of COMs is inefficient because of the lack of thermal energy…