E. Buenzli
A5037257350- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Planetary Science and Exploration
- Molecular Spectroscopy and Structure
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Gamma-ray bursts and supernovae
- Solar and Space Plasma Dynamics
- Geophysics and Gravity Measurements
- Astrophysical Phenomena and Observations
- History and Developments in Astronomy
- Spacecraft and Cryogenic Technologies
- Advanced Optical Sensing Technologies
- Optical Polarization and Ellipsometry
- Lightning and Electromagnetic Phenomena
- Space Science and Extraterrestrial Life
- Aerodynamics and Acoustics in Jet Flows
- Scientific Research and Discoveries
- High-pressure geophysics and materials
- Meteorological Phenomena and Simulations
- Historical Astronomy and Related Studies
Max Planck Institute for Astronomy
2010-2022
ETH Zurich
2009-2020
Max Planck Society
2014-2019
University of Arizona
2012-2014
The study of dynamical processes in protoplanetary disks is essential to understand planet formation. In this context, transition are prime targets because they at an advanced stage disk clearing and may harbor direct signatures evolution. paper, we aim derive new constraints on the structure MWC 758, detect non-axisymmetric features their origin. We obtained infrared polarized intensity observations 758 with SPHERE/VLT 1.04 microns resolve scattered light a smaller inner working angle...
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...
Most directly imaged giant exoplanets are fainter than brown dwarfs with similar spectra. To explain their relative underluminosity, unusually cloudy atmospheres have been proposed. However, multiple parameters varying between any two objects, it remained difficult to observationally test this idea. We present a new method, sensitive time-resolved Hubble Space Telescope near-infrared spectroscopy, study rotating L/T transition (2M2139 and SIMP0136). The observations provide spatially...
Transitional disks represent a short stage of the evolution circumstellar material. Studies dust grains in these objects can provide pivotal information on mechanisms planet formation. Dissimilarities spatial distribution small (micron-size) and large (millimeter-size) have recently been pointed out. Constraints be obtained by imaging scattered light at near-infrared wavelengths. We aim resolving structures surface layer transitional (with particular emphasis inner 10 - 50 AU), thus...
We present H-band Very Large Telescope/NACO polarized light images of the Herbig Ae/Be star HD 169142 probing its protoplanetary disk as close ∼01 to star. Our trace face-on out ∼17 (∼250 AU) and reveal distinct substructures for first time: (1) inner (≲20 appears be depleted in scattering dust grains; (2) an unresolved rim is imaged at ∼25 AU; (3) annular gap extends from ∼40 70 (4) local brightness asymmetries are found on opposite sides gap. discuss different explanations observed...
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...
We present two epochs of MPG/ESO 2.2 m GROND simultaneous six-band (r'i'z' JHK) photometric monitoring the closest known L/T transition brown dwarf binary WISE J104915.57−531906.1AB. report here first resolved variability both T0.5 and L7.5 components. obtained 4 hr focused observations on night 2013 April 22 (UT), as well defocused (unresolved) 16 (UT). note a number robust trends in our light curves. The r' i' curves appear to be anti-correlated with z' H for component unresolved curve. In...
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...
Beating bands in substellar atmospheres Brown dwarfs are objects with masses that between those of large planets and small stars. They share many features gas giant planets, particularly conditions their atmospheres. Apai et al. analyzed how the infrared brightness three brown changes over time. Several perplexing can be explained if clouds rotating within generate beat patterns. Such seen optical images Jupiter but best match Neptune. The results shed light on atmospheric physics around Sun...
We present $Spitzer$/IRAC Ch1 and Ch2 monitoring of six brown dwarfs during 8 different epochs over the course 20 months. For four dwarfs, we also obtained simulataneous $HST$/WFC3 G141 Grism spectra two derived light curves in five narrow-band filters. Probing pressure levels atmospheres, multi-wavelength our targets all exhibit variations, shape evolves timescale a rotation period, ranging from 1.4 h to 13 h. compare shapes estimate phase shifts between observed at wavelengths by comparing...
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...
As gas giant planets and brown dwarfs radiate away the residual heat from their formation, they cool through a spectral type transition L to T, which encompasses dissipation of cloud opacity appearance strong methane absorption. While there are hundreds known T-type dwarfs, first generation directly-imaged exoplanets were all L-type. Recently, Kuzuhara et al. (2013) announced discovery GJ 504 b, T dwarf exoplanet. b provides unique opportunity study atmosphere new exoplanet with ~500 K...
Heterogeneous clouds or temperature perturbations in rotating brown dwarfs produce variability the observed flux. We report time-resolved simultaneous observations of variable T6.5 dwarf 2MASSJ22282889-431026 over wavelength ranges 1.1-1.7 microns and broadband 4.5 microns. Spectroscopic were taken with Wide Field Camera 3 on board Hubble Space Telescope photometry Spitzer Telescope. The object shows sinusoidal infrared a period 1.4 hr at most wavelengths peak-to-peak amplitudes between...
Condensate clouds strongly impact the spectra of brown dwarfs and exoplanets. Recent discoveries variable L/T transition argued for patchy in at least some ultracool atmospheres. This study aims to measure frequency level spectral variability search correlations with type. We used HST/WFC3 obtain spectroscopic time series 22 types ranging from L5 T6 1.1-1.7 $\mu$m $\approx$40 min per object. Using Bayesian analysis, we find 6 confident $(p>95\%)$ relative flux one wavelength region...
Debris disks offer valuable insights into the latest stages of circumstellar disk evolution, and can possibly help us to trace outcomes planetary formation processes. In age range 10 100\,Myr, most gas is expected have been removed from system, giant planets (if any) must already formed, terrestrial may be on-going. Pluto-sized planetesimals, their debris released in a collisional cascade, are under mutual gravitational influence, which result non-axisymmetric structures disk. High angular...
Context. The SAO 206462 (HD 135344B) disk is one of the few known transitional disks showing asymmetric features in scattered light and thermal emission. Near-infrared scattered-light images revealed two bright outer spiral arms an inner cavity depleted dust. Giant protoplanets have been proposed to account for morphology. Aims. We aim search giant planets responsible and, case non-detection, constrain recent planet predictions using data detection limits. Methods. obtained new high-contrast...
We present Subaru/HiCIAO H-band high-contrast images of the debris disk around HIP 79977, whose pres- ence was recently inferred from an infrared excess. Our resolve for first time, allowing characterization its shape, size, and dust grain properties. use angular differential imaging (ADI) to reveal geometry in unpolarized light out a radius ~2", as well polarized (PDI) measure degree scattering polarization ~1.5". In order strike favorable balance between suppression stellar halo...
The morphological evolution of dusty disks around young (few Myr-old) stars is pivotal to better understand planet formation. Since both dust grains and the global disk geometry evolve on short timescale, high-resolution imaging a sample objects may provide important hints towards such an evolution. We enlarge protoplanetary imaged in polarized light with by observing Herbig Ae/Be HD163296, HD141569A, HD150193A. integrate our data previous datasets paint larger picture their morphology....
The binary brown dwarf WISE J104915.57−531906.1 (also Luhman 16AB), composed of a late-L and early-T dwarf, is prototypical L/T transition flux reversal located at distance only 2 pc. 16B known variable whose light curves evolve rapidly. We present spatially resolved spectroscopic time-series 16A B covering 6.5 hr using the Hubble Space Telescope/WFC3 1.1–1.66 μm. small, count-dependent variability beginning observations likely stems from instrumental systematics; appears non-variable above...