相关论文: Freeze-out and coagulation in pre-protostellar col…
We study the chemical evolution of interstellar grain mantle by varying the physical parameters of the interstellar medium (ISM). To mimic the exact interstellar condition, gas grain interactions via accretion from the gas phase and…
We perform a complete census of molecular ions with an abundance larger than 1e-10 in the protostellar shock L1157-B1 by means of an unbiased high-sensitivity survey obtained with the IRAM-30m and Herschel/HIFI. By means of an LVG radiative…
Disentangling the different stages of the star-formation process, in particular in the high-mass regime, is a challenge in astrophysics. Chemical clocks could help alleviating this problem, but their evolution strongly depends on many…
There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and…
We model the production of OH+, H2O+, and H3O+ in interstellar clouds, using a steady state photodissociation region code that treats the freeze-out of gas species, grain surface chemistry, and desorption of ices from grains. The code…
Among many physical processes involved in star formation, radiation transfer is one of the key processes since it dominantly controls the thermodynamics. Because metallicities control opacities, they are one of the important environmental…
Thermal ionization is a critical process at temperatures T > 10 3 K, particularly during star formation. An increase in ionization leads to a decrease in nonideal magnetohydrodynamics (MHD) resistivities, which has a significant impact on…
We investigate dust dynamics and evolution during the formation of a protostellar accretion disk around intermediate mass stars via 2D numerical simulations. Using three different detailed dust models, compact spherical particles, fractal…
Aims: The production of molecular hydrogen and its deuterated forms onto carbonaceous dust grains is investigated in detail. The goal of this study is to estimate the importance of the chemistry occuring on grain surfaces for the…
Complex organic molecules (COMs) have been identified in different environments in star- forming regions. Laboratory studies show that COMs form in the solid state, on icy grains, typically following a non-energetic (atom-addition) or…
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…
Abridged Context: Snowlines during star and disk formation are responsible for a range of effects during the evolution of protostars, such as setting the chemical composition of the envelope and disk. This in turn influences the formation…
Even today in our Galaxy, stars form from gas cores in a variety of environments, which may affect the properties of resulting star and planetary systems. Here we study the role of pressure, parameterized via ambient clump mass surface…
Aims: We aim to investigate the abundances of light deuterium-bearing species such as HD, H2D+ and D2H+ in a gas-grain chemical model including an extensive description of deuterium and spin state chemistry, in physical conditions…
The formation of molecular hydrogen in the interstellar medium takes place on the surfaces of dust grains. Hydrogen molecules play a role in gas-phase reactions that produce other molecules, some of which serve as coolants during…
Recent observations indicate that mm/cm-sized grains may exist in the embedded protostellar disks. How such large grains grow from the micron size (or less) in the earliest phase of star formation remains relatively unexplored. In this…
Cosmic rays (CR) play an important role in dense molecular cores, affecting their thermal and dynamical evolution and initiating the chemistry. Several studies have shown that the formation of protostellar discs in collapsing clouds is…
The quantity of NH3 produced on grain surfaces in the prestellar core is thought to be one of the determining factors regarding the chemical complexity achievable at later stages of stellar birth. In order to investigate how this quantity…
Methods. We have modelled a sample of ~800 nearby galaxies, spanning a wide range of metallicity, gas fraction, specific star formation rate and Hubble stage. We have derived the dust properties of each object from its spectral energy…
Most of our knowledge regarding molecular clouds and the early stages of star formation stems from molecular spectral-line observations. However, the various chemical and radiative-transfer effects, in combination with projection effects,…