A5072407168- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Magnetic and Electromagnetic Effects
- Atmospheric Ozone and Climate
- Scientific Research and Discoveries
- Advanced Thermodynamic Systems and Engines
- Solar and Space Plasma Dynamics
- Adaptive optics and wavefront sensing
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Impact of Light on Environment and Health
- History and Developments in Astronomy
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Phase Equilibria and Thermodynamics
Max Planck Institute for Astronomy
2018-2022
Max Planck Society
2018-2019
University of Chile
2016-2018
Millennium Science Initiative
2018
Kiel University
2013-2017
Diego Portales University
2016-2017
Abstract We present the first part of our Disks ARound T Tauri Stars with SPHERE (DARTTS-S) survey: observations eight stars that were selected based on their strong (sub)millimeter excesses using SPHERE/IRDIS polarimetric differential imaging in J and H bands. All successfully detect disks, which appear vastly different size, from ≈80 au scattered light to >400 au, display total polarized disk fluxes between 0.06% 0.89% stellar flux. For five these we are able determine three-dimensional...
We introduce the Ophiuchus DIsc Survey Employing ALMA (ODISEA), a project aiming to study entire population of Spitzer-selected protoplanetary discs in Molecular Cloud (~300 objects) from both millimeter continuum and CO isotopologues data. Here we present 1.3 mm/230 GHz images 147 targets at 0.2" (28 au) resolution typical rms 0.15 mJy. detect total 133 discs, including individual components 11 binary systems 1 triple system. Fifty-three these are spatially resolved. find clear...
Planets are born in protostellar disks, which now observed with enough resolution to address questions about internal gas flows. Candidates for driving the flows include magnetic forces, but ionization state estimates suggest much of mass decouples from fields. Thus, hydrodynamical instabilities could play a major role. We investigate disk dynamics under conditions typical T Tauri system, using global 3D radiation hydrodynamics simulations embedded particles and 70 cells per scale height....
Context. Near-IR polarimetric images of protoplanetary disks enable us to characterize substructures that might be due the interaction with (forming) planets. The available census is strongly biased toward massive around old stars, however. Aims. DARTTS program aims at alleviating this bias by imaging a large number T Tauri stars diverse properties. Methods. DARTTS-S employs VLT/SPHERE image polarized scattered light from disks. In parallel, DARTTS-A provides ALMA same targets for comparison...
Context. Imaged in the gap of a transition disk and found at separation about 195 mas (~22 au) from its host star position angle 155°, PDS 70 b is most robustly detected young planet to date. This system therefore unique laboratory for characterizing properties planetary systems stage their formation. Aims. We aim trace direct indirect imprints on gas dust emission circumstellar order study this ~5 Myr system. Methods. obtained ALMA band 7 observations continuum 12 CO (3 – 2) combined them...
A large fraction of stars is found to be part binary or higher-order multiple systems. The ubiquity planets around single raises the question if and how in systems may form. Protoplanetary disks are birthplaces planets, their characterization crucial order understand planet formation process. Our aim characterize morphology GG Tau disk, one largest most massive circumbinary disks, trace evidence for binary-disk interactions. We obtained observations polarized scattered light using...
We present a detailed multi-wavelength characterization of the multi-ring disk HD 169142. report new ALMA observations at 3 mm and analyze them together with archival 0.89 1.3 data. Our resolve three out four rings in previously seen high-resolution A simple parametric model is used to estimate radial profile dust optical depth, temperature, density, particle size distribution. find that multiple ring features are produced by annular accumulations large particles, probably associated gas...
We present new data of the protoplanetary disc surrounding Herbig Ae/Be star HD 169142 obtained in very broad-band (VBB) with Zurich imaging polarimeter (ZIMPOL), a sub-system Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) at Very Large Telescope (VLT). Our Polarimetric Differential Imaging (PDI) observations probe as close 0.03" (3.5au) to and are able trace out ~1.08" (~126au). find an inner hole, bright ring bearing substructures around 0.18" (21au),...
Abstract We present ALMA 1.3 mm continuum observations at (25 au) resolution of Elias 2–24, one the largest and brightest protoplanetary disks in Ophiuchus Molecular Cloud, we report presence three partially resolved concentric gaps located ∼20, 52, 87 au from star. perform radiative transfer modeling disk to constrain its surface density temperature radial profile place structure context mechanisms capable forming narrow such as condensation fronts dynamical clearing by actively planets. In...
ALMA observations revealed recently polarised radiation of several protoplanetary disks in the (sub-)millimetre wavelength range. Besides self-scattering large particles, thermal emission by elongated grains is a potential source for detected polarisation signal. We calculate dependent absorption and intrinsic spheroidally shaped, micrometre sub-millimetre sized dust using discrete dipole approximation. In particular, we analyse impact grain porosity which appears to be present when small...
Abstract Magnetic fields significantly influence the evolution of protoplanetary discs and formation planets, following predictions numerous magnetohydrodynamic (MHD) simulations. However, these are yet observationally unconstrained. To validate on magnetic discs, we apply 3D radiative transfer simulations polarized emission aligned aspherical dust grains that directly link global non-ideal MHD to Atacama Large Millimeter/submillimeter Array (ALMA) observations. Our show it is feasible...
Context: The role of magnetic fields in the star formation process is a contentious matter debate. In particular, no clear observational proof exists general influence by during initial collapse molecular clouds. Aims: Our aim to examine and their on wide range spatial scales low-mass star-forming regions. Method: We trace large-scale field structure 10^3-10^5 AU local environment Bok globules through optical near-infrared polarimetry combine these measurements with existing submillimeter...
We present new astrometric measurements of the components in T Tauri system, and derive orbits masses. was observed during science verification time extreme adaptive optics facility SPHERE at VLT. combine positions with recalibrated NACO-measurements data from literature. Model fits for Tau Sa Sb around each other N yield orbital elements individual masses stars Sb. Our orbit Sa/Sb is good agreement recent results, which indicates that enough has been a reliable fit. The total mass S...
The understanding of (sub-)millimetre polarisation has made a leap forward since high-resolution imaging with ALMA came available. Amongst other effects, self-scattering (i.e., scattering thermal dust emission on grains) is thought to be the origin millimetre polarisation. This opens first window direct measurement grain sizes in regions optically thick continuum as it can found protoplanetary disks and star-forming regions. However, newly derived values are usually around ${\sim}100\,\mu$m...
CONTEXT. Little is known about the planetary systems around single white dwarfs although there strong evidence that they do exist. AIMS. We performed a pilot study with extreme-AO system on Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) Very Large Telescopes (VLT) to look for giant planets young dwarf, GD 50. METHODS. were awarded science verification time new ESO instrument SPHERE. Observations made InfraRed Dual-band Imager and Spectrograph in classical imaging mode H band....
(Sub-)millimetre observations of the polarized emission aligned aspherical dust grains enable us to study magnetic fields within protoplanetary disc. However, interpretation these is complex. One must consider various effects that alter measured signal, such as shape grains, efficiency grain alignment, field properties and projection signal along line sight. We aim at analysing by disentangling on polarization in context 3D radiative transfer simulations. For this purpose, we developed a...
We present the optical imaging polarimetric observations of comet C/2009 P1(Garradd) at three different phase angles e.g., 28.2$^\circ$, 28.1$^\circ$ and 21.6$^\circ$. The were carried out using IUCAA Faint Object Spectrograph Camera mounted on Cassegrain focus 2-m Telescope IGO, IUCAA, Pune in R$_{comet}$, R photometric bands, 21 22 March 2012 ARIES Imaging Polarimeter 1.04-m Sampurnanand ARIES, Nainital band, 23 May 2012. show presence a jet activity rotational gradient treated image...
Planets form in young circumstellar disks called protoplanetary disks. However, it is still difficult to catch planet formation in-situ. Nevertheless, from recent ALMA/SPHERE data, encouraging evidence of the direct and indirect presence embedded planets has been identified around stars: co-moving point sources, gravitational perturbations, rings, cavities, emission dips or shadows cast on The interpretation these observations needs a robust physical framework deduce complex disk geometry....
Abstract Circumbinary disks are common around post-asymptotic giant branch (post-AGB) stars with a stellar companion on orbital timescales of few 100 to 1000 days. The presence disk is usually inferred from the system’s spectral energy distribution and confirmed, for sub-sample, by interferometric observations. We used Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument Very Large Telescope obtain extreme adaptive optics assisted scattered light images post-AGB binary...