Related papers: Oxygen fractionation in dense molecular clouds
Many chemical models of dense interstellar clouds predict that the majority of gas-phase elemental nitrogen should be present as N2, with an abundance approximately five orders of magnitude less than that of hydrogen. As a homonuclear…
Evolution of grain mantles in various interstellar environment is studied. We concentrate mainly on water, methanol, carbon di-oxide, which constitute nearly 90% of the grain mantle. We investigate how the production rates of these…
The chemical evolution of galaxies that undergo an episode of massive and rapid accretion of metal-poor gas is investigated with models using both simplified and detailed nucleosynthesis recipes. The rapid decrease of the oxygen abundance…
We present the results of astrochemical modeling of complex organic molecules (COMs) in the ice and gas of the prestellar core L1544 with the recently updated MONACO rate equations-based model. The model includes, in particular,…
We study the evolution of molecular hydrogen on the grain surfaces and in the gas phase using both the rate equation (which tracks the average number of molecules) and the master equation (which tracks the expectation values of molecules).…
We present new models of the deuterium chemistry in protoplanetary disks, including, for the first time, multiply deuterated species. We use these models to explore whether observations in combination with models can give us clues as to…
Oxygen ($O_2$) is one of the most important elements required to sustain life. The concentration of $O_2$ on Earth has been accumulated over millions of years and has a direct connection with that of $CO_2$. Further, $CO_2$ plays an…
Oxidation of graphite and subsequent exfoliation leads to single layer graphene oxide (GO). GO has found many applications across diverse fields including medicinal chemistry, catalysis as well as a precursor for graphene. One of the key…
The stable isotopologues of water have been used in atmospheric and climatic studies for over fifty years, because the temperature-dependent preferential condensation of heavy isotopologues during phase changes makes them useful diagnostics…
Dust and gas energetics are incorporated into a cluster-scale simulation of star formation in order to study the effect of heating and cooling on the star formation process. We build on our previous work by calculating separately the dust…
We investigate the formation of the recently detected HNSO molecule using quantum chemical calculations on ices and astrochemical models in tandem. Our results indicate that HNSO is efficiently produced on grain surfaces through reactions…
Context. Time dependent gas-grain chemistry can help us understand the layered structure of species deposited onto the surface of grains during the lifetime of a protoplanetary disk. The history of trapping important quantities of carbon-…
We describe how Monte Carlo simulation within the grand canonical ensemble can be applied to the study of phase behaviour in polydisperse fluids. Attention is focused on the case of fixed polydispersity in which the form of the `parent'…
The addition of metals to any gas can significantly alter its evolution by increasing the rate of radiative cooling. In star-forming environments, enhanced cooling can potentially lead to fragmentation and the formation of low-mass stars,…
We investigate the uncertainties affecting the temperature profiles of dense cores of interstellar clouds. In regions shielded from external ultraviolet radiation, the problem is reduced to the balance between cosmic ray heating, line…
The Central Molecular Zone (CMZ) contains most of the mass of our Galaxy but its star formation rate is one order of magnitude lower than in the Galactic disc. This is likely related to the fact that the bulk of the gas in the CMZ is in a…
We present an observational and theoretical study of the ionization fraction in several massive cores located in regions that are currently forming stellar clusters. Maps of the emission from the J = 1-> O transitions of C18O, DCO+, N2H+,…
New observations of 11 compact galaxies in the 12CO J=2-1 and J=3-2 transitions and literature data have been used to construct accurate line ratios in matched beams allowing LVG modelling of physical parameters. Fitting a single gas…
Abbreviation. Thermal diffusion is one of the basic processes for the mobility and formation of species on cosmic dust grains. Recent laboratory measurements have found that the diffusion pre-exponential factor can differ from that for…
The formation of CO2 in quiescent regions of molecular clouds is not yet fully understood, despite CO2 having an abundance of around 10-34 % H2O. We present a study of the formation of CO2 via the non-energetic route CO + OH on non-porous…