A5002533486- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Molecular Spectroscopy and Structure
- Adaptive optics and wavefront sensing
- Atmospheric Ozone and Climate
- Advanced Combustion Engine Technologies
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Bee Products Chemical Analysis
- Space Exploration and Technology
- High-pressure geophysics and materials
- Calibration and Measurement Techniques
- Chemical Thermodynamics and Molecular Structure
- Image and Signal Denoising Methods
- Advanced Image Processing Techniques
- Computer Graphics and Visualization Techniques
- Advanced Fiber Optic Sensors
- Superconducting and THz Device Technology
- Solar and Space Plasma Dynamics
- Semiconductor Lasers and Optical Devices
- Geophysics and Gravity Measurements
- Advanced X-ray Imaging Techniques
KU Leuven
2018-2024
Institute of Astronomy
2020-2024
VIB-KU Leuven Center for Microbiology
2020-2022
Institut de Planétologie et d'Astrophysique de Grenoble
2011-2020
University of Exeter
2015-2020
Vilnius University
2019
Herzberg Institute of Astrophysics
2019
Centre National de la Recherche Scientifique
2011-2016
Université Grenoble Alpes
2011-2016
Université Joseph Fourier
2011-2015
Context. PIONIER stands for Precision Integrated-Optics Near-infrared Imaging ExpeRiment. It combines four 1.8m Auxilliary Telescopes or 8m Unit of the Very Large Telescope Interferometer (ESO, Chile) using an integrated optics combiner. The instrument was at IPAG in December 2009 and commissioned Paranal Observatory October 2010. has provided scientific observations since November
Context. It is now generally accepted that the near-infrared excess of Herbig AeBe stars originates in dust a circumstellar disk. Aims. The aims this article are to infer radial and vertical structure these disks at scales order one au, properties grains. Methods. program objects (51 total) were observed with H-band (1.6micron) PIONIER/VLTI interferometer. largest baselines allowed us resolve (at least partially) structures few tenths an au typical distances hundred parsecs. Dedicated...
Young stars are surrounded by a circumstellar disk of gas and dust, within which planet formation can occur. Gravitational forces in multiple star systems disrupt the disk. Theoretical models predict that if is misaligned with orbital plane stars, should warp break into precessing rings, phenomenon known as tearing. We present observations triple system GWOrionis, finding evidence for Our images show an eccentric ring planes outer The casts shadows on strongly warped intermediate region If...
We present the first near-IR milli-arcsecond-scale image of a post-AGB binary that is surrounded by hot circumbinary dust. A very rich interferometric data set in six spectral channels was acquired IRAS08544-4431 with new RAPID camera on PIONIER beam combiner at Very Large Telescope Interferometer (VLTI). broadband \textit{H} band reconstructed combining all using SPARCO method. spatially separate building blocks system our milliarcsecond-resolution image. Our dissection reveals dust...
The innermost astronomical unit in protoplanetary disks is a key region for stellar and planet formation, as exoplanet searches have shown large occurrence of close-in planets that are located within the first au around their host star. We aim to reveal morphology disk inner rim using near-infrared interferometric observations with milli-arcsecond resolution provided by infrared interferometry. provide reconstructed images 15 objects selected from Herbig AeBe survey carried out PIONIER at...
Post-asymptotic giant branch (post-AGB) binaries are surrounded by massive disks of gas and dust that similar to protoplanetary around young stars. We assembled a catalog all known Galactic post-AGB with disks. explore the correlations between different observables aim learning more about potential disk-binary interactions. compiled spectral energy distributions 85 binary systems. built color-color diagram differentiate disk morphologies traced infrared excess. categorized types searched for...
Context. Jets are commonly detected in post-asymptotic giant branch (post-AGB) binaries and originate from an accretion process onto the companion of post-AGB primary. These jets revealed by high-resolution spectral time series. Aims. This paper is part a In this work, we move away our previous parametric modelling include self-similar wind model that allows physical properties to be characterised. describes magnetically driven thin disk threaded large-scale, near equipartition vertical...
We aim at resolving the circumstellar environment around beta Pic in near-infrared order to study inner planetary system (< 200 mas, i.e., ~4 AU). Precise interferometric fringe visibility measurements were obtained over seven spectral channels dispersed across H band with four-telescope VLTI/PIONIER interferometer. Thorough analysis of data was performed measure stellar angular diameter and search for material. detected emission that accounts 1.37% +/- 0.16% flux is located within...
Abstract High-mass multiples might form via fragmentation of self-gravitational disks or alternative scenarios such as disk-assisted capture. However, only a few observational constraints exist on the architecture and disk structure high-mass protobinaries their accretion properties. Here, we report discovery close (57.9 ± 0.2 mas = 170 au) protobinary, IRAS17216-3801, where our VLTI/GRAVITY+AMBER near-infrared interferometry allows us to image circumstellar around individual components with...
The emergence of optical interferometers with three and more telescopes allows image reconstruction astronomical objects at the milliarcsecond scale. However, some contain components very different spectral energy distributions (SED; i.e. temperatures), which produces strong chromatic effects on interferograms that have to be managed care by algorithms. For example, gray approximation for process results in a degraded if total (u, v)-coverage given supersynthesis is used. relative flux...
Context. In this paper, we focus on post-asymptotic giant branch (post-AGB) binaries and study the interaction between different components of these complex systems. These comprise post-AGB primary, a main sequence secondary, circumbinary disk, as well fast bipolar outflow (jet) launched by companion. We obtained well-sampled time series high resolution optical spectra over last decade provide basis our study. Aims. aim to use time-series data quantify velocity density structure jets in nine...
Hi-5 is the L'-band (3.5-4.0 <i>μ</i>m) high-contrast imager of Asgard, an instrument suite in preparation for visitor focus VLTI. The system optimized and high-sensitivity imaging within diffraction limit a single UT/AT telescope. It designed as double-Bracewell nulling producing spectrally-dispersed (R=20, 400, or 2000) complementary outputs simultaneous photometric self-calibration purposes. In this paper, we present update project with particular on overall architecture,...
High angular resolution observations of young stellar objects are required to study the inner astronomical units protoplanetary disks in which majority planets form. As they evolve, gaps open up disk regions and fully dispersed within ~10 Myrs. MWC 614 is a pre-transitional object with ~10au radius gap. We present set high this including SPHERE/ZIMPOL polarimetric coronagraphic images visible, KECK/NIRC2 near-infrared aperture masking VLTI (AMBER, MIDI, PIONIER) CHARA (CLASSIC CLIMB)...
Context. Luminous Blue Variables (LBVs) are thought to be in a transitory phase between O stars on the main-sequence and Wolf-Rayet stage. Recent studies suggest that they might formed through binary interaction. Only few known systems but their multiplicity fraction is uncertain. Aims. This study aims at deriving among Galactic (confirmed candidate) LBV population. We combine multi-epoch spectroscopy long-baseline interferometry. Methods. use cross-correlation measure radial velocities....
Aims. The circumstellar environment of L2 Pup, an oxygen-rich semiregular variable, was observed to understand the evolution mass loss and shaping ejecta in late stages stellar evolution.
MWC158 is a star with the B[e] phenomenon that shows strong spectrophotometric variability (in lines and in UV visible continuum) attributed to phases of shell ejection. The evolutionary stage this was never clearly determined. Previous interferometric, spectropolarimetric spectro-interferometric studies suggest disk morphology for its environment. We investigate origin within inner astronomical unit central using near-infrared interferometric observations PIONIER at VLTI over two-year...
Post-AGB binaries are surrounded by circumbinary disks of gas and dust that similar to protoplanetary found around young stars. We aim understand the structure these identify physical phenomena at play in their very inner regions. want disk-binary interaction further investigate comparison with disks. have conducted an interferometric snapshot survey 23 post-AGB near-infrared (H-band) using VLTI/PIONIER. fitted multiwavelength visibilities closure phases purely geometrical models increasing...
Many properties of circumbinary discs around evolved post-asymptotic giant branch (post-AGB) binary systems are similar to those protoplanetary young stars. The deficits near-infrared (near-IR) flux in the spectral energy distributions (SEDs) these hints towards large dust-free cavities that reminiscent transition as commonly observed We aim assess size inner rim 6 post-AGB with lack near-IR like this. used resolved mid-infrared (mid-IR) high-angular resolution observations VLTI/MATISSE and...
Abstract We present Gemini Planet Imager polarized intensity imagery of HD 100453 in Y , J and K 1 bands that reveals an inner gap (9–18 au), outer disk (18–39 au) with two prominent spiral arms, azimuthally localized dark features are also Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) total images. Spectral energy distribution fitting further suggests the radial extends to au. The narrow, wedge-like shape appears similar predictions shadows cast by is misaligned respect...
Spatially resolving the inner dust cavity of transitional disks is a key to understanding connection between planetary formation and disk dispersal. The around Herbig star HD 139614 particular interest since it presents pretransitional nature with an au-sized gap, in dust, that was spatially resolved by mid-IR interferometry. Using new NIR interferometric observations, we aim characterize 0.1-10~au region HD~139614 further identify viable mechanisms for clearing. We report first...
Here we present the results of 6th biennial optical interferometry imaging beauty contest. Taking advantage a unique opportunity, red supergiant VY CMa and Mira variable R Car were observed in astronomical H-band with three 4-telescope configurations VLTI-AT array using PIONIER instrument. The community was invited to participate subsequent image reconstruction interpretation phases project. Ten groups submitted entries contest, found reasonable consistency between images obtained from...
(abridged) Stable circumbinary discs around evolved post-Asymptotic Giant branch (post-AGB) binary systems show many similarities with protoplanetary young stellar objects. These can provide constraints on both evolution and the formation of macrostructures within circumstellar discs. Here we focus one post-AGB system: IRAS08544-4431. We aim to refine physical model IRAS08544-4431 a radiative transfer treatment continue near-infrared mid-infrared interferometric analysis covering H-, K-, L-,...
Context. T Tauri stars are low-mass young whose disks provide the setting for planet formation. Despite this, their structure is poorly understood. We present new infrared interferometric observations of SU Aurigae circumstellar environment that offer resolution three times higher and a better baseline position angle coverage than previous observations. Aims. aim to investigate characteristics material around Aur, constrain disk geometry, composition inner dust rim structure. Methods. The...