A5057522345- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Molecular Spectroscopy and Structure
- Adaptive optics and wavefront sensing
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Space Exploration and Technology
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
- Optical Polarization and Ellipsometry
- Spacecraft and Cryogenic Technologies
- High-pressure geophysics and materials
- Geophysics and Gravity Measurements
- Optical Systems and Laser Technology
- Spectroscopy and Laser Applications
- Spectroscopy and Chemometric Analyses
- Spectroscopy Techniques in Biomedical and Chemical Research
- Isotope Analysis in Ecology
- Pulsars and Gravitational Waves Research
- Particle Accelerators and Free-Electron Lasers
- Particle accelerators and beam dynamics
- Gyrotron and Vacuum Electronics Research
Leiden University
2015-2024
Ollscoil na Gaillimhe – University of Galway
2023-2024
University of Amsterdam
2017-2024
Leiden Observatory
2014-2022
Sorbonne Université
2022
Université Paris Cité
2022
Laboratoire d’études spatiales et d’instrumentation en astrophysique
2022
Observatoire de Paris
2022
Centre National de la Recherche Scientifique
2022
Université de Versailles Saint-Quentin-en-Yvelines
2022
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...
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...
Context. The protoplanetary disk around the F-type star HD 135344B (SAO 206462) is in a transition stage and shows many intriguing structures both scattered light thermal (sub-)millimeter emission which are possibly related to planet formation processes.
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...
Abstract We present scattered light images of the TW Hya disk performed with Spectro-Polarimetric High-contrast Exoplanet REsearch instrument in Polarimetric Differential Imaging mode at 0.63, 0.79, 1.24, and 1.62 μ m. also H2/H3-band angular differential imaging (ADI) observations. Three distinct radial depressions polarized intensity distribution are seen, around ≈85, ≈21, ≲6 au. 21 The overall has a high degree azimuthal symmetry; is somewhat brighter than average toward south darker...
[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...
The variety of observed protoplanetary disks in polarimetric light motivates a taxonomical study to constrain their evolution and establish the current framework this type observations. We classified 58 with available observations into six major categories (Ring, Spiral, Giant, Rim, Faint, Small disks) based on appearance scattered light. re-calculated stellar disk properties from newly GAIA DR2 related these categories. More than half our sample shows sub-structures. For remaining sources,...
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...
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...
The substellar companion HD206893b has recently been discovered by direct imaging of its disc-bearing host star with the SPHERE instrument. We investigate atypical properties companion, which reddest near-infrared colours among all known objects, either orbiting a or isolated, and we provide comprehensive characterisation star-disc-companion system. conducted follow-up adaptive optics spectro-imaging SPHERE, multiinstrument star. obtain R=30 spectrum from 0.95 to 1.64 micron additional...
HD$\,$169142 is an excellent target to investigate signs of planet-disk interaction due the previous evidence gap structures. We performed J-band (~1.2{\mu}m) polarized intensity imaging HD169142 with VLT/SPHERE. observe scattered light down 0.16" (~19 au) and find inner a significantly reduced flux. confirm previously detected double ring structure peaking at 0.18" (~21 0.56" (~66 au), marginally detect faint third 0.70"-0.73" (~82-85 au). explore dust evolution models in disk perturbed by...
Context . The SPHERE “planet finder” is an extreme adaptive optics (AO) instrument for high resolution and contrast observations at the Very Large Telescope (VLT). We describe Zurich Imaging Polarimeter (ZIMPOL), visual focal plane subsystem of SPHERE, which pushes limits current AO systems to shorter wavelengths, higher spatial resolution, much improved polarimetric performance. Aims present a detailed characterization SPHERE/ZIMPOL should be useful optimal planning improving data reduction...
While planet formation is thought to occur early in the history of a protoplanetary disk, presence planets embedded disks, or other processes driving disk evolution, might be traced from their imprints on structure. We observed T Tauri star HD 143006, located 5-11 Myr-old Upper Sco region, polarized scattered light with VLT/SPHERE at near-infrared wavelengths, reaching an angular resolution ~0.037" (~6 au). obtained two datasets, one 145 mas diameter coronagraph, and without, enabling us...
Context. Polarimetric imaging is one of the most effective techniques for high-contrast and characterization protoplanetary disks, it has potential becoming instrumental in exoplanets. The Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument installed on Very Large Telescope (VLT) contains InfraRed Dual-band Imager Spectrograph (IRDIS) with a dual-beam polarimetric (DPI) mode, which offers capability obtaining linear polarization images at high contrast resolution. Aims....
We image with unprecedented spatial resolution and sensitivity disk features that could be potential signs of planet-disk interaction. Two companion candidates have been claimed in the around young Herbig Ae/Be star HD100546. Thus, this object serves as an excellent target for our investigation natal environment giant planets. exploit power extreme adaptive optics operating conjunction new high-contrast imager SPHERE to HD100546 scattered light. obtain first polarized light observations...
Abstract Gas-rich circumstellar disks are the cradles of planet formation. As such, their evolution will strongly influence resulting population. In ESO DESTINYS large program, we study these within first 10 Myr development with near-infrared scattered-light imaging. Here present VLT/SPHERE polarimetric observations nearby class II system SU Aur in which resolve disk down to scales ∼7 au. addition new SPHERE observations, utilize VLT/NACO, HST/STIS, and ALMA archival data. The data show...
For several transition disks (TDs), dark regions interpreted as shadows have been observed in scattered light imaging and are hypothesized to originate from misalignments between distinct disk regions. We aim investigate the presence of TDs. study inner geometries 20 well-known with VLTI/GRAVITY observations use complementary $^{12}$CO $^{13}$CO molecular line data ALMA derive orientation outer fit simple models GRAVITY inclination position angles. The were derived Keplerian fits velocity...
Context. While it is generally assumed that Class II sources evolve largely in isolation from their environment, many still lie close to molecular clouds and may continue interact with them. This result late accretion of material onto the disk can significantly influence processes planet formation. Aims. In order systematically study infall gas disks, we identify candidate vicinity a reflection nebula (RN) be undergoing this process. Methods. First targeted known kilo-au scale structures -...
Abstract Despite rapidly growing disk observations, it remains a mystery what primordial dust aggregates look like and the physical chemical properties of their constituent grains (monomers) are in young planet-forming disks. Confrontation models with observations to answer this has been notorious task because we have abandon commonly used assumption, perfectly spherical grains, take into account particles complex morphology. In Letter, present first thorough comparison between near-infrared...
The sample of planet-forming disks observed by high-contrast imaging campaigns over the last decade is mature enough to enable demographical analysis individual star-forming regions. We present full census Taurus sources with VLT/SPHERE polarimetric images available. whole sums up 43 targets (of which 31 have not been previously published) corresponding one-fifth Class II population in and about half such objects that are observable. A large fraction apparently made isolated faint (equally...