A5089452758- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Calibration and Measurement Techniques
- Gamma-ray bursts and supernovae
- Optical Systems and Laser Technology
- Planetary Science and Exploration
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- Advanced optical system design
- Astrophysical Phenomena and Observations
- CCD and CMOS Imaging Sensors
- Geophysics and Gravity Measurements
- Geology and Paleoclimatology Research
- Molecular Spectroscopy and Structure
- Solar and Space Plasma Dynamics
- Isotope Analysis in Ecology
- Space Exploration and Technology
- History and Developments in Astronomy
- Astronomical and nuclear sciences
- Spectroscopy Techniques in Biomedical and Chemical Research
- Optical Polarization and Ellipsometry
Laboratoire d’Astrophysique de Marseille
2015-2024
Aix-Marseille Université
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Château Gombert
2015-2024
Sorbonne Université
2020-2022
LAM Foundation
2018-2022
Université Paris Cité
2020-2022
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2020-2022
Observatoire de Paris
2020-2022
Université de Versailles Saint-Quentin-en-Yvelines
2022
With a combination of adaptive optics imaging and multi-epoch common proper motion search, we have conducted large volume-limited (D ≤ 75 pc) multiplicity survey A-type stars, sensitive to companions beyond 30 au. The sample for the Volume-limited A-STar (VAST) consists 435 stars: 363 stars were observed with optics, 228 searched wide 156 measured both techniques. projected separation coverage VAST extends from 45 000 A total 137 stellar resolved, including 64 new detections survey,...
Young circumstellar disks are of prime interest to understand the physical and chemical conditions under which planet formation takes place. Only very few detections candidates within these exist, most them currently suspected be disk features. In this context, transition around young star PDS 70 is particular interest, due its large gap identified in previous observations, indicative ongoing formation. We aim search for presence planets structures disk-planet interactions other evolutionary...
The direct detection of exoplanets has been the subject intensive research in recent years. Data obtained with future high-contrast imaging instruments optimized for giant planets are strongly limited by speckle noise. Specific observing strategies and data analysis methods, such as angular spectral differential imaging, required to attenuate noise level possibly detect faint planet flux. Even though these methods very efficient at suppressing speckles, photometry is dominated residuals....
Observations of circumstellar environments to look for the direct signal exoplanets and scattered light from disks has significant instrumental implications. In past 15 years, major developments in adaptive optics, coronagraphy, optical manufacturing, wavefront sensing data processing, together with a consistent global system analysis have enabled new generation high-contrast imagers spectrographs on large ground-based telescopes much better performance. One most productive is...
The SHINE program is a large high-contrast near-infrared survey of 600 young, nearby stars. It aimed at searching for and characterizing new planetary systems using VLT/SPHERE's unprecedented high-angular resolution imaging capabilities. also intends placing statistical constraints on the occurrence orbital properties giant planet population orbits as function stellar host mass age to test formation theories. We use IRDIS dual-band imager IFS integral field spectrograph SPHERE acquire...
Aims: We aim to characterize the orbital and atmospheric properties of PDS 70 b, which was first identified on May 2015 in course SHINE survey with SPHERE, extreme adaptive-optics instrument at VLT. Methods: obtained new deep SPHERE/IRDIS imaging SPHERE/IFS spectroscopic observations b. The astrometric baseline now covers 6 years allows us perform an analysis. For time, we present spectrophotometry young planet almost entire near-infrared range (0.96 3.8 micrometer). use different models...
As a part of our ongoing Volume-limited A-Star (VAST) adaptive optics survey, we have obtained observations 26 binary systems with projected separations <100 AU, 13 which sufficient historical measurements to allow for refinement their orbital elements. For each system an estimated orbit, the dynamical mass was compared from mass-magnitude relations. Discrepancies between and theoretical can be explained by presence previously unresolved spectroscopic component, or non-solar metallicity...
Context. Clouds are ubiquitous in exoplanet atmospheres and they represent a challenge for the model interpretation of their spectra. When generating large number spectra, complex cloud models often prove too costly numerically, whereas more efficient may be overly simplified. Aims. We aim to constrain atmospheric properties directly imaged planet HR 8799e with free retrieval approach. Methods. used our radiative transfer code petitRADTRANS which we coupled PyMultiNest tool. added effect...
The SPHERE (Spectro-Polarimetric High-contrast Exoplanet Research) planet finder instrument for ESO's VLT telescope, scheduled first light in 2011, aims to detect giant extra-solar planets the vicinity of bright stars by aid an extreme-AO turbulence compensation system and characterize objects found through spectroscopic polarimetric observations. Dual imaging observations within Y, J, H Ks atmospheric windows (~0.95 - 2.32μm) will be done IRDIS cryogenic camera. We describe briefly science...
Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence massive planets at relatively large separations, but dedicated surveys are required to estimate frequency similar systems. To measure first estimation giant exoplanetary systems orbital separation around A-stars, we have conducted a deep-imaging survey young (8−400 Myr), nearby (19−84 pc) A- and F-stars search for substellar in ~10−300 AU range. The sample 42 combines all A-stars observed...
The planetary system discovered around the young A-type HR8799 provides a unique laboratory to: a) test planet formation theories, b) probe diversity of architectures at these separations, and c) perform comparative (exo)planetology. We present exploit new near-infrared images integral-field spectra four gas giants surrounding obtained with SPHERE, finder instrument Very Large Telescope, during commissioning science verification phase (July-December 2014). With data, we contribute to...
51 Eridani b is an exoplanet around a young (20 Myr) nearby (29.4 pc) F0-type star, recently discovered by direct imaging. Being only 0.5" away from its host star it well suited for spectroscopic analysis using integral field spectrographs. We aim to refine the atmospheric properties of this and further constrain architecture system searching additional companions. Using SPHERE instrument at VLT we extend spectral coverage planet complete Y- H-band range provide photometry in K12-bands...
Understanding the diversity of planets requires to study morphology and physical conditions in protoplanetary disks which they form. We observed spatially resolved disk around ~10 Myr old HD 100453 polarized scattered light with SPHERE/VLT at optical near-infrared wavelengths, reaching an angular resolution ~0.02", inner working angle ~0.09". detect up ~0.42" (~48 au) a cavity, rim azimuthal brightness variations inclination 38 degrees, two shadows symmetric spiral arms. The arms originate...
We present the performance of Integral Field Spectrograph (IFS) SPHERE, high-contrast imager for ESO VLT telescope designed to perform imaging and spectroscopy extrasolar planets, obtained from tests performed at Institute de Plan\'etologie et d'Astrophysique Grenoble facility during integration phase instrument.} {The were using instrument software purposely prepared SPHERE. The output data reduced applying SPHERE reduction handling software, adding an improved spectral deconvolution...
The system of four planets around HR8799 offers a unique opportunity to probe the physics and chemistry at play in atmospheres self-luminous young (~30 Myr) planets. We recently obtained new photometry low-resolution (R~30) spectra d e with SPHERE instrument (paper III). In this paper IV), we compare available known objects atmospheric models (BT-SETTL14, Cloud-AE60, Exo-REM) characterize properties find that HR8799d are well reproduced by those L6-L8 dusty dwarfs discovered field, among...
[Abridged] Context. The young systems PZ Tel and HD 1160, hosting known low-mass companions, were observed during the commissioning of new planet finder SPHERE with several imaging spectroscopic modes. Aims. We aim to refine physical properties architecture both systems. Methods. use data REM observations, as well literature unpublished from VLT/SINFONI, VLT/NaCo, Gemini/NICI, Keck/NIRC2. Results. derive photometry confirm nearly daily photometric variability A. Using spanning 38 yr, we show...
In anticipation of the VLT/SPHERE planet imager guaranteed time programs, we have conducted a preparatory survey 86 stars between 2009 and 2013 in order to identify new faint comoving companions ultimately carry out comprehensive analysis occurence giant planets brown dwarf at wide (10-2000 AU) orbits around young, solar-type stars. We used NaCo VLT explore occurrence rate dwarfs typically 0.1 8''. Diffraction-limited observations H-band combined with angular differential imaging enabled us...
Understanding the formation and evolution of giant planets ($\ge$1 $M_{Jup}$) at wide orbital separation ($\ge$5 AU) is one goals direct imaging. Over past 15 years, many surveys have placed strong constraints on occurrence rate wide-orbit giants, mostly based non-detections, but very few tried to make a link with planet theories. In present work, we combine results our previously published VLT/NaCo large program 12 imaging constitute statistical sample 199 FGK stars within 100 pc, including...
Context. Circumstellar disks and self-luminous giant exoplanets or companion brown dwarfs can be characterized through direct-imaging polarimetry at near-infrared wavelengths. SPHERE/IRDIS the Very Large Telescope has capabilities to perform such measurements, but uncalibrated instrumental polarization effects limit attainable polarimetric accuracy. Aims. We aim characterize correct of complete optical system, that is, telescope SPHERE/IRDIS. Methods. created a detailed Mueller matrix model...
HR4796A is surrounded by a debris disc, observed in scattered light as an inclined ring. Past observations raised several questions. First, strong brightness asymmetry detected polarized reflected recently challenged our understanding of scattering the dust particles this system. Secondly, morphology ring strongly suggests presence planets, although no planets have been to date. We obtained high-angular resolution coronagraphic images circumstellar environment around with VLT/SPHERE during...
GJ758 B is a brown dwarf companion to nearby (15.76 pc) solar-type, metal-rich (M/H = +0.2 dex) main-sequence star (G9V) that was discovered with Subaru/HiCIAO in 2009. From previous studies, it has drawn attention as being the coldest (~600K) ever directly imaged around neighboring star. We present new high-contrast data obtained during commissioning of SPHERE instrument at VLT. The Y-, J-, H-, and Ks-bands dual-band imaging (DBI) mode IRDIS, providing broad coverage full near-infrared...