A5057045238- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Advanced Chemical Physics Studies
- Atmospheric chemistry and aerosols
- Ionosphere and magnetosphere dynamics
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Atomic and Molecular Physics
- Spacecraft and Cryogenic Technologies
- Phase Equilibria and Thermodynamics
- Nuclear Physics and Applications
- Methane Hydrates and Related Phenomena
- Magnetic and Electromagnetic Effects
- Gas Dynamics and Kinetic Theory
- Planetary Science and Exploration
- Medical Imaging Techniques and Applications
Centre de Recherche Astrophysique de Lyon
2015-2025
École Normale Supérieure de Lyon
2014-2024
Centre National de la Recherche Scientifique
2014-2024
Université Claude Bernard Lyon 1
2014-2024
Max Planck Institute for Astronomy
2010-2019
Max Planck Society
2010-2019
École Normale Supérieure - PSL
2012-2014
Laboratoire de Géologie de l’École Normale Supérieure
2014
Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères
2008-2012
Astrophysique, Instrumentation et Modélisation
2010-2011
We report the results of radiation-magnetohydrodynamics calculations in context high-mass star formation, using for first time a self-consistent model photon emission (i.e., via thermal and radiative shocks) with high resolution necessary to properly resolve magnetic braking effects shocks on scales <100 AU. investigate combined field, turbulence, transfer early phases collapse fragmentation massive dense cores. identify new mechanism that inhibits initial cores where field interplay. show...
In this paper, we provide a more accurate description of the evolution magnetic flux redistribution during prestellar core collapse by including resistive terms in magnetohydrodynamics (MHD) equations. We focus particularly on impact ambipolar diffusion. use adaptive mesh refinement code RAMSES to carry out such calculations. The resistivities required calculate diffusion were computed using reduced chemical network charged, neutral and grain species. inclusion leads formation barrier...
Stars and more particularly massive stars, have a drastic impact on galaxy evolution. Yet the conditions in which they form collapse are still not fully understood. In particular, influence of magnetic field clumps is relatively unexplored, it thus great relevance context formation stars to investigate its impact. We perform high resolution, MHD simulations hundred solar masses, turbulent magnetized clouds, using adaptive mesh refinement code RAMSES. compute various quantities such as mass...
Context. Radiative transfer has a strong impact on the collapse and fragmentation of prestellar dense cores.
The formation of protoplanetary discs during the collapse molecular dense cores is significantly influenced by angular momentum transport, notably magnetic torque. In turn, evolution field determined dynamical processes and non-ideal MHD effects such as ambipolar diffusion. Considering simple relations between various timescales characteristic magnetized collapse, we derive an expression for early disc radius, $ r \simeq 18 \, {\rm AU} \left({η_{\rm AD} / 0.1 s}} \right)^{2/9} \left({B_z...
In order to study the fragmentation of massive dense cores, which constitute cluster cradles, we observed with PdBI in most extended configuration continuum at 1.3 mm and CO(2-1) emission four cores. We detect dust condensations down ~0.3 Msun separate millimeter sources 0.4" or ~1000 AU, comparable sensitivities separations reached optical/infrared studies clusters. The high angular resolution images reveal high-velocity knots usually aligned previously known outflow directions. This,...
Context . The transport of angular momentum is fundamental during the formation low-mass stars; too little removal and rotation ensures stellar densities are never reached, much absence means no protoplanetary disks can form. Magnetic diffusion seen as a pathway to resolving this long-standing problem. Aims We aim investigate impact including resistive magnetohydrodynamics (MHD) in simulations gravitational collapse 1 M ⊙ gas sphere, from molecular cloud protostellar seed; second Larson...
GEMS is an IRAM 30m Large Program whose aim determining the elemental depletions and ionization fraction in a set of prototypical star-forming regions. This paper presents first results from dark cloud TMC 1. Extensive millimeter observations have been carried out with telescope (3 mm 2 mm) 40m Yebes (1.3 cm 7 to determine fractional abundances CO, HCO
Abstract A complete understanding of the initial conditions high-mass star formation and what processes determine multiplicity requires study magnetic field in young massive cores. Using Atacama Large Millimeter/submillimeter Array (ALMA) 250 GHz polarization observations (0 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mrow> <mml:mi>.</mml:mi> </mml:mrow> <mml:mi>″</mml:mi> </mml:mover> </mml:math> 3 = 1000 au) ALMA 220...
It is established that both radiative transfer and magnetic field have a strong impact on the collapse fragmentation of prestellar dense cores, but no consistent calculation exists yet at such scales. We present original AMR calculations including (in ideal MHD limit) transfer, within Flux Limited Diffusion approximation, 1 solar mass core. compare results with performed barotropic EOS. show has an important fragmentation, through cooling or heating gas, complementary field. A larger yields...
We develop a detailed chemical network relevant to the conditions characteristic of prestellar core collapse. solve system time-dependent differential equations calculate equilibrium abundances molecules and dust grains, with size distribution given by size-bins for these latter. These are used compute different non-ideal magneto-hydrodynamics resistivities (ambipolar, Ohmic Hall), needed carry out simulations protostellar For first time in this context, we take into account evaporation...
In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study density structure 19 selected be at similar evolutionary stages, for which their relative level was assessed in previous work. We inferred cores through simultaneous fit radial intensity profiles 450 and 850 μm (or 1.2 mm two cases) spectral energy distribution, assuming spherical symmetry that temperature decrease with radius following power-laws. Even though...
The early evolution of massive cluster progenitors is poorly understood. We investigate the fragmentation properties from 0.3 pc to 0.06 scales a homogenous sample infrared-quiet clumps within 4.5 kpc selected ATLASGAL survey. Using ALMA 7m array we detect compact dust continuum emission towards all targets, and find that fragmentation, at these scales, limited. mass distribution fragments uncovers large fraction cores above 40 $M_\odot$, corresponding dense (MDCs) with masses up ~400...
Sulphur is one of the most abundant elements in Universe. Surprisingly, sulphuretted molecules are not as expected interstellar medium, and identity main sulphur reservoir still an open question. Our goal to investigate H$_{2}$S chemistry dark clouds, this stable molecule a potential reservoir. Using millimeter observations CS, SO, H$_{2}$S, their isotopologues, we determine physical conditions abundances along cores TMC 1-C, 1-CP, Barnard 1b. The gas-grain model Nautilus then used explore...
We present high resolution (~ 30 au) ALMA Band 6 dust polarization observations of VLA 1623. The 1623 data resolve compact ~ 40 au inner disks around the two protobinary sources, 1623-A and 1623-B, also an extended 180 ring 1623-A. This was previously identified as a large disk in lower-resolution observations. detect highly structured toward with typical fractions 1.7% 2.4%, respectively. components show distinct morphologies. have uniform angles aligned their minor axes. morphology is...
Star formation begins with the gravitational collapse of a dense core inside molecular cloud. As progresses, centre to heat up as it becomes optically thick. The temperature and density in eventually reach high enough values where fusion reactions can ignite; protostar is born. This sequence events entail many physical processes, which radiative transfer paramount importance. Many simulations protostellar make use grey treatment coupled hydrodynamics. However, interstellar gas dust opacities...
Our aim is to study the thermal and dynamical evolution of protoplanetary disks in global simulations, including physics radiation transfer magneto-hydrodynamic (MHD) turbulence caused by magneto-rotational instability. We develop a radiative method based on flux-limited diffusion approximation that includes frequency dependent irradiation central star. This hybrid scheme implemented PLUTO code. The focus our implementation performance method. Using an optimized Jacobi preconditioned...
The low-mass star formation evolutionary sequence is relatively well-defined both from observations and theoretical considerations. first hydrostatic core the protostellar equilibrium object that formed during process. Using state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations, we aim to provide predictions for dust continuum emission cores. We investigate collapse fragmentation of magnetized one solar mass prestellar dense cores evolution using RAMSES...
In the theory of star formation, first hydrostatic core (FHSC) phase is a critical step in which condensed object emerges from prestellar core. This lasts about one thousand years, very short time compared with lifetime cores, and therefore hard to detect unambiguously. We present IRAM Plateau de Bure observations Barnard 1b dense molecular core, combining detections H2CO CH3OH spectral lines dust continuum at 2.3" resolution (~ 500 AU). The two compact cores B1b-N B1b-S are detected 2mm,...
The Barnard 1b core shows signatures of being at the earliest stages low-mass star formation, with two extremely young and deeply embedded protostellar objects. Hence, this is an ideal target to study structure chemistry first objects formed in collapse prestellar cores. We present ALMA Band 6 spectral line observations ~0.6'' angular resolution towards 1b. have extracted spectra both protostars, used a Local Thermodynamic Equilibrium (LTE) model reproduce observed profiles. B1b-S rich...
Abstract We present high-resolution (∼35 au) ALMA Band 6 1.3 mm dust polarization observations of IRAS 16293. These spatially resolve the across two protostellar sources and toward filamentary structures between them. The inferred magnetic field have complicated throughout region. In particular, we find that is aligned parallel to three structures. characterize physical properties structure bridges 16293A 16293B estimate a strength 23–78 mG using Davis-Chandrasekhar-Fermi method. construct...
Dust plays a key role during star, disk and planet formation. Yet, its dynamics the protostellar collapse remains poorly investigated field. Recent studies seem to indicate that dust may decouple efficiently from gas these early stages. We aim understand how much in which regions grains concentrate phases of collapse, see it depends on properties initial cloud solid particles. use multiple species solver grid-based code RAMSES perform various simulations dusty collapses. hydrodynamical MHD...
Abstract Protoplanetary disks form through angular momentum conservation in collapsing dense cores. In this work, we perform the first simulations with a maximal resolution down to astronomical unit (au) of protoplanetary disk formation, collapse 1000 M ⊙ clumps, treating self-consistently both non-ideal magnetohydrodynamics ambipolar diffusion as well radiative transfer flux-limited approximation including stellar feedback. Using adaptive mesh-refinement code RAMSES , investigate influence...