Related papers: Molecular Evolution in Collapsing Prestellar Cores…
We have investigated the evolution and distribution of molecules in collapsing prestellar cores via numerical chemical models, adopting the Larson-Penston solution and its delayed analogues to study collapse. Molecular abundances and…
The gravitational collapse of a spherical cloud core is investigated by numerical calculations. The initial conditions of the core lie close to the critical Bonnor-Ebert sphere with a central density of \sim 10^4 cm^{-3} in one model…
The physical conditions in a collapsing cloud can be traced by observations of molecular lines. To correctly interpret these observations the abundance distributions of the observed species need to be derived. The chemistry in a collapsing…
We study the changes in physical and chemical conditions during the collapse of a pre--protostellar core, starting from initial conditions appropriate to a dense molecular cloud and proceeding to the ``completely depleted'' limit. We follow…
We combine dynamical and non-equilibrium chemical modeling of evolving prestellar molecular cloud cores, and explore the evolution of molecular abundances in the contracting core. We model both magnetic cores, with varying degrees of…
We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense-cloud core to a protostellar core, by solving a gas-grain reaction network applied to a 1-D radiative hydrodynamic model…
We develop analytic approximations to the density evolution of prestellar cores, based on the results of hydrodynamical simulations. We use these approximations as input for a time-dependent gas-grain chemical code to investigate the…
We investigate the chemical evolution of a collapsing core that starts from a hydrostatic core and finally form a low-mass protostar. New multiphase gas-grain models that include bulk diffusion and photon penetration are simulated by the…
We discuss recent models of chemical evolution in the developing and collapsing protostellar envelopes associated with low-mass star formation. In particular, the effects of depletion of gas-phase molecules onto grain surfaces is…
Understanding the chemical evolution in star-forming cores is a necessary pre-condition to correctly assess physical conditions when using molecular emission. We follow the evolution of chemistry and molecular line profiles through the…
Observations of low mass protostars which probe small enough size scales to be within likely CO depletion regions show the highest [NH2D]/[NH3] ratios yet measured, of 4--33%. These molecular D/H ratios are higher than those measured on…
(Abridged) The aim of this study is to investigate the chemical evolution from the prestellar phase to the formation of the disk, and to determine the impact that the chemical composition of the cold and dense core has on the final…
We have compared molecular line emission to dust continuum emission and modeled molecular lines using Monte Carlo simulations in order to study the depletion of molecules and the ionization fraction in three preprotostellar cores, L1512,…
Combining the co-evolving chemistry, hydrodynamics and radiative transfer is an important step for star formation studies. It allows both a better link to observations and a self-consistent monitoring of the magnetic dissipation in the…
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,…
This work explores the differences between static and dynamically evolving physico-chemical models of pre-stellar cores. A 3D MHD model of a pre-stellar core embedded in a dynamic star-forming cloud is post-processed using sequentially dust…
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…
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…
An ever growing number of observational and theoretical evidence suggests that the deuterated fraction (column density ratio between a species containing D and its hydrogenated counterpart, Dfrac) is an evolutionary indicator both in the…
We investigate molecular evolution in a star-forming core that is initially a hydrostatic starless core and collapses to form a low-mass protostar. The results of a one-dimensional radiation-hydrodynamics calculation are adopted as a…