相关论文: Molecular Evolution in Collapsing Prestellar Cores…

We perform numerical magnetohydrodynamic (MHD) simulations of the gravitational collapse and fragmentation of a cylindrical molecular cloud with the help of the FLASH code. The cloud collapses rapidly along its radius without any signs of…

We investigate protostellar collapse of molecular cloud cores by numerical simulations, taking into account turbulence and magnetic fields. By using the adaptive mesh refinement technique, the collapse is followed over a wide dynamic range…

Understanding the collapse of dense molecular cloud cores to stellar densities and the subsequent evolution of the protostar is of importance to model the feedback effects such an object has on its surrounding environment, as well as…

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…

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,…

Deuteration is a crucial tool to understand the complexity of interstellar chemical processes, especially when they involve the interplay of gas-phase and grain-surface chemistry. In the case of multiple deuteration, comparing observation…

Motivated by recent observations which detect an outer boundary for starless cores, and evidence for time-dependent mass accretion in the Class 0 and Class I protostellar phases, we reexamine the case of spherical isothermal collapse in the…

H2 formation is an important process in post-shock regions, since H2 is an active participant in the cooling and shielding of the environment. The onset of H2 formation therefore has a strong effect on the temperature and chemical evolution…

The complexity of physico-chemical models of star formation is increasing, with models that take into account new processes and more realistic setups. These models allow astrochemists to compute the evolution of chemical species throughout…

We study molecular hydrogen formation in and on solids. We construct a model with surface sites and bulk sites capable of describing (1) the motion and exchange of H and H_2 between surface and bulk, (2) the recombination of H and…

We study deuterium fractionation in two massive starless/early-stage cores C1-N and C1-S in Infrared Dark Cloud (IRDC) G028.37+00.07, first identified by Tan et al. (2013) with ALMA. Line emission from multiple transitions of $\rm N_2H^+$…

A prevailing theory for the interstellar production of complex organic molecules (COMs) involves formation on warm dust-grain surfaces, via the diffusion and reaction of radicals produced through grain-surface photodissociation of stable…

Ice nucleation and growth are critical in many fields, including atmospheric science, cryobiology, and aviation. However, understanding the detailed mechanisms of ice crystal growth remains challenging. In this work, crystallization at the…

We study the evolution of the [Eu/Fe] ratio in the Galactic halo by means of a stochastic chemical evolution model considering merging neutron stars as polluters of europium. We improved our previous stochastic chemical evolution model by…

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).…

A proper modelling of the cosmic-ray ionisation rate within gas clouds is crucial to describe their chemical evolution accurately. However, this modelling is computationally demanding because it requires the propagation of cosmic rays…

Seven isolated, nearby low-mass starless molecular cloud cores have been observed as part of the Herschel key program Earliest Phases of Star formation (EPoS). By applying a ray-tracing technique to the obtained continuum emission and…

Context: The depletion of heavy elements in cold cores of interstellar molecular clouds can lead to a situation where deuterated forms of H_3^+ are the most useful spectroscopic probes of the physical conditions. Aims: The aim is to predict…

Properties of candidate stars, forming out of molecular clouds, depend on the ambient conditions of the parent cloud. We present a series of 2D and 3D simulations of fragmentation of molecular clouds in starburst regions as well as clouds…

We have measured the deuterium fractionation (through the column density ratio N(N2D+)/N(N2H+)) and the CO depletion factor (ratio between expected and observed CO abundance) in a sample of 10 high-mass protostellar candidates, in order to…