A5021045762- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Spacecraft and Cryogenic Technologies
- Space Exploration and Technology
- Gamma-ray bursts and supernovae
- Planetary Science and Exploration
- Astronomical Observations and Instrumentation
- Advanced Combustion Engine Technologies
- Astrophysical Phenomena and Observations
- Fluid Dynamics Simulations and Interactions
- Ionosphere and magnetosphere dynamics
- Adaptive optics and wavefront sensing
- SAS software applications and methods
- Pulsars and Gravitational Waves Research
- Advanced Thermodynamic Systems and Engines
- Solar and Space Plasma Dynamics
- Engineering Structural Analysis Methods
- Scientific Measurement and Uncertainty Evaluation
- Atmospheric Ozone and Climate
- Geomagnetism and Paleomagnetism Studies
- Spaceflight effects on biology
- Elasticity and Material Modeling
Centre de Recherche Astrophysique de Lyon
2013-2024
École Normale Supérieure de Lyon
2011-2023
Université Claude Bernard Lyon 1
2012-2023
Centre National de la Recherche Scientifique
2012-2023
Australian National University
2018
University of California, Berkeley
2016
Observatoire de Lyon
2011-2015
Universitat de Barcelona
2014
Centre de Recherche en Linguistique Appliquée
2007
European Southern Observatory
1998-2001
We present and discuss the photometric spectroscopic evolution of peculiar SN 1998bw, associated with GRB 980425, through an analysis optical near-IR data collected at ESO-La Silla. The data, spanning period from day -9 to +376 (relative B maximum), have shown that this supernova (SN) was unprecedented, although somewhat similar 1997ef. Maximum expansion velocities as high 3 × 104 km s-1 some extent mask its resemblance other Type Ic SNe. At intermediate phases, between photospheric fully...
Planet formation is thought to occur in discs around young stars by the aggregation of small dust grains into much larger objects. The growth from pebbles and planetesimals planets now fairly well understood. intermediate stage has however been found be hindered radial-drift fragmentation barriers. We identify a powerful mechanism which overcomes both Its key ingredients are (i) backreaction on gas, (ii) grain (iii) large-scale gradients. pile-up growing fragmenting modifies gas structure...
HD 181327 is a young F5/F6V star belonging to the Beta Pictoris moving group (12 Myr). It harbors an optically thin belt of circumstellar material at 90 AU. We aim study dust properties in details, and constrain gas-to-dust ratio. obtained far-IR observations with Herschel/PACS instrument, 3.2 mm ATCA array. The geometry constrained newly reduced HST/NICMOS images that break degeneracy between disk properties. use radiative transfer code GRaTer compute large grid models, we identify grain...
Protoplanetary discs are now routinely observed and exoplanets, after the numerous indirect discoveries, starting to be directly imaged. To better understand planet formation process, next step is detection of forming planets or signposts young still in their disc, such as gaps. A spectacular example ALMA science verification image HL Tau showing gaps rings its disc. study observability gaps, we ran 3D hydrodynamical simulations a gas dust disc containing 5 M J gap-opening characterised...
Context: While sub-micron- and micron-sized dust grains are generally well mixed with the gas phase in protoplanetary disks, larger will be partially decoupled as a consequence have different distribution from that of gas. This has ramifications for predictions observability which gas-only studies provide an inaccurate picture. Specifically, criteria gap opening presence planet been studied phase, whereas situation can quite layer once reach mm sizes, is what observed by ALMA. Aims: We aim...
Our objective is to study the vertical dust distribution in circumbinary ring of binary system GG Tau and search for evidence stratification, one first steps expected occur during planet formation. We present a simultaneous analysis four scattered light images spanning range wavelength from 800 nm 3800 compare them with (i) parametric prescription (ii) results SPH bi-fluid hydrodynamic calculations. The hydrodynamical calculations stratification both reproduce observed brightness profiles...
[Abridged] Aims: We provide predictions for ALMA observations of planet gaps that account the specific spatial distribution dust results from consistent gas+dust dynamics. Methods: In a previous work, we ran full 3D, two-fluid Smoothed Particle Hydrodynamics (SPH) simulations embedded in T Tauri disk different masses and grain sizes. this resulting distributions are passed to Monte Carlo radiative transfer code MCFOST construct synthetic images wavebands. then use simulator produce include...
Context. To form metre-sized pre-planetesimals in protoplanetary discs, growing grains have to decouple from the gas before they are accreted onto central star during their phase of fast radial migration and thus overcome so-called "radial-drift barrier" (often inaccurately referred as "metre-size barrier"). Aims. predict outcome motion dust discs whose surface density temperature follow power-law profiles, with exponent p q respectively. We investigate both Epstein Stokes drag regimes which...
Photophoresis is a physical process based on momentum exchange between an illuminated dust particle and its gaseous environment. Its net effect in protoplanetary discs (PPD) the outward transport of solid bodies from hot to cold regions. This naturally leads formation ring-shaped features where piles up. In this work, we study dynamical effects photophoresis PPD by including photophoretic force two-fluid (gas+dust) smoothed hydrodynamics (SPH) code developed Barrière-Fouchet et al. (2005)....
How does the cavity size in circumbinary discs depend on disc and binary properties? We investigate by simulating cavities carved companions using smoothed particle hydrodynamics (SPH). find that a is quickly opened dynamical time, while set viscous time. In agreement with previous findings, we long term sizes of 2-5 times semi-major axis, increasing eccentricity decreasing aspect ratio. When considering binaries inclined respect to three regimes: i) evolve towards coplanar orbit have large...
In a companion paper, we present novel method for the spectroscopic detection of low-luminosity secondary companions binary stars. An interesting application field is identification very low-mass stars as late-type main-sequence To provide simple tool based on our method, developed Binary Spectral Disentangling (BiSpeD), python repository that provides toolkit processing and analyzing observations. The main task BiSpeD find2c, which aims to calculate mass ratio (q) single-lined from analysis...
We present the results of a three dimensional, locally isothermal, non-self-gravitating SPH code which models protoplanetary disks with two fluids: gas and dust. ran simulations 1 star surrounded by 0.01 disk comprising 99% 1% dust in mass extending from 0.5 to AU. The grain size ranges 10-6 m 10 for low resolution ( particles) 10-4 cm high simulations. Dust grains are slowed down sub-Keplerian lose angular momentum, forcing them migrate towards central settle midplane. drag efficiency...
The Protoplanetary Discussions conference --- held in Edinburgh, UK, from 7th --11th March 2016 included several open sessions led by participants. This paper reports on the discussions collectively concerned with multiphysics modelling of protoplanetary discs, including self-consistent calculation gas and dust dynamics, radiative transfer chemistry. After a short introduction to each these disciplines isolation, we identify series burning questions grand challenges associated their...
Vortices are one of the most promising mechanisms to locally concentrate millimeter dust grains and allow formation planetesimals through gravitational collapse. The outer disk around binary system HD 142527 is known for its large horseshoe structure with azimuthal contrasts 3-5 in gas surface density about 50 dust. Using 13CO C18O J = 3-2 transition lines, we detect kinematic deviations Keplerian rotation, which consistent presence a vortex crescent, as well few spirals regions disk....
Context: In protoplanetary discs, micron-sized dust grows to form millimetre- centimetre-sized pebbles but encounters several barriers during its evolution. Collisional fragmentation and radial drift impede further growth planetesimal size. Fluffy grains have been hypothesised solve these problems. While porosity leads faster grain growth, the implied values obtained from previous simulations were larger than suggested by observations. Aims: this paper, we study influence of on evolution...
Aims. We investigate the behaviour of dust in protoplanetary disks under action gas drag presence a planet. Our goal is twofold: to determine spatial distribution depending on grain size and planet mass, therefore provide framework for interpretation coming observations future studies planetesimal growth.
Aims. In order to understand the first stages of planet formation, when tiny grains aggregate form planetesimals, one needs simultaneously model grain growth, vertical settling and radial migration dust in protoplanetary disks. this study, we implement an analytical prescription for growth into a 3D two-phase hydrodynamics code its effects on distribution
Radio and near-infrared observations have observed dozens of protoplanetary disks that host spiral arm features. Numerical simulations shown companions may excite density waves in via companion-disk interaction. However, the lack direct observational evidence for spiral-driving poses challenges to current theories Here we report multi-epoch binary system HD 100453 with Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) facility at Very Large Telescope. By recovering features...
We report the discovery of optical counterpart to GRB 980326. Its rapid decay can be characterized by a power law with exponent -2.10 +/- 0.13 and constant underlying source at R_c=25.5 0.5. colours 2.1 days after burst imply spectral slope -0.66 0.70. The gamma-ray spectrum as observed BATSE shows that it is among 4% softest bursts ever recorded. argue may reason for non-detection some low-energy afterglows GRBs.
One of the main problems in planet formation, hampering growth small dust to planetesimals, is so-called radial-drift barrier. Pebbles cm dm sizes are thought drift radially across protoplanetary discs faster than they can grow larger sizes, and thus be lost star. To overcome this barrier, has slowed down or stopped, needs sped up. In paper, we investigate role porosity on both growth. We have developed a model for evolution during grain applied it numerical simulations discs. find that...