A5034745280- Astrophysics and Star Formation Studies
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Advanced Chemical Physics Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Spectroscopy and Laser Applications
- Atomic and Molecular Physics
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Atmospheric chemistry and aerosols
- Distributed and Parallel Computing Systems
- Advanced Combustion Engine Technologies
- Gamma-ray bursts and supernovae
- History and advancements in chemistry
- Astrophysics and Cosmic Phenomena
- Catalysis and Oxidation Reactions
- Mass Spectrometry Techniques and Applications
- Chemical Thermodynamics and Molecular Structure
- Quantum, superfluid, helium dynamics
- Spacecraft and Cryogenic Technologies
- Methane Hydrates and Related Phenomena
- Analytical Chemistry and Chromatography
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
Laboratoire d'Astrophysique de Bordeaux
2016-2025
Université de Bordeaux
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Observatoire Aquitain des Sciences de l'Univers
2005-2023
Max Planck Institute for Radio Astronomy
2015
Max Planck Society
2015
Laboratoire de Recherche Scientifique
2013
The Ohio State University
2005-2008
Columbus Center
2007
We present a novel chemical database for gas-phase astrochemistry. Named the KInetic Database Astrochemistry (KIDA), this consists of reactions with rate coefficients and uncertainties that will be vetted to greatest extent possible. Submissions measured calculated are welcome, studied by experts before inclusion into database. Besides providing kinetic information interstellar medium, KIDA is planned contain such data planetary atmospheres circumstellar envelopes. Each year, subset in...
While warm dense gas is prevalent around low-mass protostars, the presence of complex saturated molecules—the chemical inventory characteristic hot cores—has remained elusive in such environments. Here we report results an IRAM 30 m study molecular composition associated with protostar IRAS 16293-2422. Our observations highlight extremely rich organic this source abundant amounts O- and N-bearing molecules as formic acid, HCOOH, acetaldehyde, CH3CHO, methyl formate, CH3OCHO, dimethyl ether,...
Chemical models used to study the chemical composition of gas and ices in interstellar medium are based on a network reactions associated rate coefficients. These coefficients partially compiled from data literature, when available. We present this paper kida.uva.2014, new updated version kida.uva public gas-phase first released 2012. In addition description many specific updates, we illustrate changes predicted abundances molecules for cold dense cloud conditions as compared with results...
Aims.The gas-phase abundance of methanol in dark quiescent cores the interstellar medium cannot be explained by chemistry. In fact, only possible synthesis this species appears to production on surfaces dust grains followed desorption into gas. Yet, evaporation is inefficient for heavy molecules such as at typical temperature 10 K. It necessary then consider non-thermal mechanisms desorption. But, if are considered methanol, they must all surface species.
We present an extended version of the two-phase gas–grain code nautilus to three-phase modelling gas and grain chemistry cold cores. In this model, both mantle surface are considered as chemically active. also take into account competition among reaction, diffusion evaporation. The model predictions confronted ice observations in envelope low-mass massive young stellar objects well towards background stars. Modelled gas-phase abundances compared species observed TMC-1 (CP) L134N dark clouds....
Molecular hydrogen is the most abundant molecule in universe. It first one to form and survive photo-dissociation tenuous environments. Its formation involves catalytic reactions on surface of interstellar grains. The micro-physics process has been investigated intensively last 20 years, parallel new astrophysical observational modeling progresses. In perspectives probable revolution brought by future satellite JWST, this article written present what we think know about H2 a variety
Sulphur-bearing species are often used to probe the physical structure of star forming regions interstellar medium, but chemistry sulphur in these is still poorly understood.In dark clouds, supposed be depleted under a form which unknown despite numerous observations and chemical modeling studies that have been performed.In order improve chemistry, we propose an enhancement network using experimental theoretical literature.We test effect updated on outputs three phases gas-grain model for...
Virtually all detailed gas-phase models of the chemistry dense interstellar clouds exclude polycyclic aromatic hydrocarbons (PAHs). This omission is unfortunate because from few studies that have been done on subject, it known inclusion PAHs can affect strongly. We added to our network determine role they play in cold cores. Initially, only neutral and negatively charged PAH species was considered, since assumed positively are little importance. Subsequently, this assumption checked...
We investigate molecular evolution in a star-forming core that is initially hydrostatic starless and collapses to form low-mass protostar. The results of one-dimensional radiation-hydrodynamics calculation are adopted as physical model the core. first derive radii at which CO large organic species sublimate. sublimation central region starts shortly before formation When protostar born, radius extends 100 AU, inside $\lesssim 10$ AU hotter than K, some evaporate. calculate temporal variation...
Abridged: We detail and benchmark two sophisticated chemical models developed by the Heidelberg Bordeaux astrochemistry groups. The main goal of this study is to elaborate on a few well-described tests for state-of-the-art astrochemical codes covering range physical conditions processes, in particular those aimed at constraining current future interferometric observations protoplanetary disks. consider three models: cold molecular cloud core, hot an outer region T Tauri disk. Our network...
We present a new interstellar chemical gas-phase reaction network for time-dependent kinetics that can be used modeling high-temperature sources up to ≈800 K. This contains an extended set of reactions based on the Ohio State University (OSU) network. The additional include processes with significant activation energies, reverse reactions, proton exchange charge and collisional dissociation. Rate coefficients already in OSU are modified H2 formation grains, ion–neutral dipole some radiative...
We survey the current situation regarding chemical modelling of synthesis molecules in interstellar medium. The present state knowledge concerning rate coefficients and their uncertainties for major gas-phase processes—ion-neutral reactions, neutral-neutral radiative association, dissociative recombination—is reviewed. Emphasis is placed on those key reactions that have been identified, by sensitivity analyses, as 'crucial' determining predicted abundances species observed These analyses...
Recent observations have revealed the existence of complex organic molecules (COMs) in cold dense cores and pre-stellar cores. The presence these such conditions is not well understood remains a matter debate since previously proposed 'warm-up' scenario cannot explain observations. In this paper, we study effect Eley–Rideal induced reaction mechanisms gas-phase carbon atoms with main ice components dust grains on formation COMs regions. Based recent experiments, use low value for chemical...
The Virtual Atomic and Molecular Data Centre (VAMDC) Consortium is a worldwide consortium which federates atomic molecular databases through an e-science infrastructure organisation to support this activity. About 90% of the inter-connected handle data that are used for interpretation astronomical spectra modelling in many fields astrophysics. Recently VAMDC has connected from radiation damage plasma communities, as well promoting publication Indian institutes. This paper describes how...
We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense cloud core to protostellar core, by solving gas–grain reaction network applied one-dimensional radiative hydrodynamic model with infalling fluid parcels. Spatial distributions of gas ice-mantle species are calculated at first-core stage, times after birth protostar. Gas-phase methanol methane more abundant than CO radii r ≲ 100 AU in but gradually decrease time, while...
Context. Unbiased spectral surveys are powerful tools to study the chemistry and physics of star forming regions, because they can provide a complete census molecular content observed lines probe physical structure source.
Recent detections of complex organic molecules in dark clouds have rekindled interest the astrochemical modeling these environments. Because its relative closeness and rich molecular complexity, TMC-1 has been extensively observed to study chemical processes taking place clouds. We use local thermodynamical equilibrium radiative transfer coupled with a Bayesian statistical method which takes into account outliers analyze data from Nobeyama spectral survey between 8 50 GHz. compute abundance...
We review the reactions involving hydrogen cyanide (HCN) and isocyanide (HNC) in dark molecular clouds to elucidate new chemical sources sinks of these isomers. find that most important for HCN–HNC system are dissociative recombination (DR) HCNH+ (HCNH+ + e−), ionic CN H3+, HCN C+, HNC with H+/He+/H3+/H3O+/HCO+, N CH2 reaction two reactions: H CCN C HNC. test effect rate constants branching ratios on predictions gas–grain models cloud conditions. The rapid keeps HCN/HNC ratio significantly...
The L1544 pre-stellar core has been observed as part of the ASAI IRAM 30 m Large Program well follow-up programs. These observations have revealed chemical richness earliest phases low-mass star-forming regions. In this paper, we focus on 21 sulphur bearing species (ions, isotopomers, and deuteration) that detected in spectral-survey through 51 transitions: CS, CCS, C3S, SO, SO2, H2CS, OCS, HSCN, NS, HCS+, NS+, H2S. We also report tentative detection (4σ level) for methyl mercaptan (CH3SH)....
This paper presents an overview of the current status Virtual Atomic and Molecular Data Centre (VAMDC) e-infrastructure, including VAMDC-connected (or to be connected) databases, updates on latest technological development within infrastructure a presentation some application tools that make use VAMDC e-infrastructure. We analyse past 10 years operation, assess their impact both field atomic molecular (A&M) physics itself heterogeneous data management in international cooperation. The...