Related papers: Oxygen fractionation in dense molecular clouds
A deep, wide-field, near-infrared imaging survey was used to construct an extinction map of the southeastern part of the California Molecular Cloud (CMC) with $\sim$ 0.5 arc min resolution. The same region was also surveyed in the…
Because the opacity of clouds in substellar mass object (SMO) atmospheres depends on the composition and distribution of particle sizes within the cloud, a credible cloud model is essential for accurately modeling SMO spectra and colors. We…
The properties of the ices that form in dense molecular clouds represent an important set of initial conditions in the evolution of interstellar and preplanetary matter in regions of active star formation. Of the various spectral features…
The form of depleted sulphur in dense clouds is still unknown. Until now, only two molecules, OCS and SO2, have been detected in interstellar ices but cannot account for the elemental abundance of sulphur observed in diffuse medium.…
Context. The increased sensitivity and high spectral resolution of millimeter telescopes allow the detection of an increasing number of isotopically substituted molecules in the interstellar medium. The 14N/ 15N ratio is difficult to…
The thermal and fragmentation properties of star-forming clouds have important consequences on the corresponding characteristic stellar mass. The initial composition of the gas within these clouds is a record of the nucleosynthetic products…
We report the results of a large-area study of water vapor along the Orion Molecular Cloud ridge, the purpose of which was to determine the depth-dependent distribution of gas-phase water in dense molecular clouds. We find that the water…
The study of the chemical evolution of glycine in the interstellar medium is one of challenging topics in astrochemistry. Here, we present the chemical modeling of glycine in hot cores using the state-of-the-art three-phase chemical model…
We report here the results of Molecular Dynamics simulations of the drift mobility of negative oxygen ions in very dense neon gas in the supercritical phase. The simulations relatively well reproduce the trend of the experimental data. The…
Thin films of Cu-W-O ternary compounds were fabricated via DC magnetron co-sputtering from Cu and W metallic targets under controlled oxygen partial pressures, followed by thermal annealing. Low-oxygen conditions favored the formation of a…
We study the gravitational fragmentation of cold accretion streams flowing into a typical first galaxy. We use a one-zone hydrodynamical model to examine the thermal evolution of the gas entering a 10^8 M_sun DM halo at z=10. The goal is to…
The question, what is the role of freeze-out of chemical species in determining the molecular abundances in the interstellar gas is a matter of debate. We investigate a theoretical case of a dense interstellar molecular cloud core by…
Deuteration is sensitive to environmental conditions in star-forming regions. To investigate NH$_2$D chemistry, we compared the spatial distribution of ortho-NH$_2$D $1_{11}^s-1_{01}^a$, NH$_3$(1,1) and NH$_3$(2,2) in 12 late-stage massive…
We discuss the connection between the chemistry of dense interstellar clouds and those characteristics of cometary matter that could be remnants of it. The chemical evolution observed to occur in molecular clouds is summarized and a model…
The type and distribution of oxygen functional groups in graphene oxide (GO) and reduced graphene oxide (RGO) remain still a subject of great debate. Local analytic techniques are required to access the chemistry of these materials at a…
Context : Despite the low cosmic abundance of deuterium (D/H ~ 1e-5), large degrees of deuterium fractionation in molecules are observed in star forming regions with enhancements that can reach 13 orders of magnitude, which current models…
Photochemistry induced by stellar UV flux should produce haze particles in exoplanet atmospheres. Recent observations indicate that haze and/or cloud layers exist in the atmospheres of exoplanets. However, photochemical processes in…
Aims. We probe the effect of turbulent diffusion on the chemistry at the interface between a cold neutral medium (CNM) cloudlet and the warm neutral medium (WNM). Methods. We perform moving grid, multifluid, 1D, hydrodynamical simulations…
The physical conditions of the Galactic center (GC) clouds moving with non-circular velocities are not well-known. We have studied the physical conditions of these clouds with the aim of better understanding the origin of the outstanding…
The recombination dynamics of $^3$P oxygen atoms on cold amorphous solid water to form triplet and singlet molecular oxygen (O$_2$) is followed under conditions representative for cold clouds. It is found that both, formation of ground…