Ryo Tazaki
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Is cosmic dust porous? Open
There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and…
Variation of the disk thickness across ice bands: A method to determine ice abundances in highly inclined protoplanetary disks Open
The James Webb Space Telescope provides unprecedented information to study ices in protoplanetary disks. However, the saturation of ice bands in highly inclined disks hinders the measurement of ice abundances using classical spectroscopy. …
Is cosmic dust porous? Open
There is a long-standing discussion in the astrophysical/astrochemical community as to the structure and morphology of dust grains in various astrophysical environments (e.g., interstellar clouds, protostellar envelopes, protoplanetary and…
View article: Multiwavelength Dust Characterization of the HL Tau Disk and Implications for Planet Formation
Multiwavelength Dust Characterization of the HL Tau Disk and Implications for Planet Formation Open
We present a comprehensive analysis of the HL Tau dust disk by modeling its intensity profiles across six wavelengths (0.45–7.9 mm) with a resolution of 0 05 (∼7 au). Using a Markov Chain Monte Carlo (MCMC) approach, we constrain key…
Multiwavelength analysis of polarized light in HD 100453 Open
HD 100453 disk is a prototypical companion-disk interaction system hosting a pair of spirals and a substellar companion. We present new noncoronagraphic high-contrast imaging observations of HD 100453 with V filter on SPHERE/ZIMPOL. We aim…
View article: WIde Separation Planets In Time (WISPIT): A Gap-clearing Planet in a Multi-ringed Disk around the Young Solar-type Star WISPIT 2
WIde Separation Planets In Time (WISPIT): A Gap-clearing Planet in a Multi-ringed Disk around the Young Solar-type Star WISPIT 2 Open
In the past decades, several thousand exoplanet systems have been discovered around evolved, main-sequence stars, revealing a wide diversity in their architectures. To understand how the planet formation process can lead to vastly differen…
View article: Multi-Wavelength Dust Characterization of the HL Tau Disk and Implications for Planet Formation
Multi-Wavelength Dust Characterization of the HL Tau Disk and Implications for Planet Formation Open
We present a comprehensive analysis of the HL Tau dust disk by modeling its intensity profiles across six wavelengths (0.45 to 7.9 mm) with a resolution of 0.05 arcsec ($\sim7$ au). Using a Markov Chain Monte Carlo (MCMC) approach, we cons…
View article: Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Evidence of planet-disk interaction in the 2MASSJ16120668-3010270 system
Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Evidence of planet-disk interaction in the 2MASSJ16120668-3010270 system Open
The architectures of exoplanet systems are likely set during the initial planet-formation phase in the circumstellar disk. To understand this process, we have to study the earliest phases of planet formation. Complex sub-structures, believ…
View article: Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Evidence of planet–disk interaction in the 2MASSJ16120668-3010270 system
Disk Evolution Study Through Imaging of Nearby Young Stars (DESTINYS): Evidence of planet–disk interaction in the 2MASSJ16120668-3010270 system Open
Context . The multitude of different architectures found for evolved exoplanet systems are in all likelihood set during the initial planet-formation phase in the circumstellar disk. To understand this process, we have to study the earliest…
DRAGyS – A comprehensive tool for extracting scattering phase functions in protoplanetary disks Open
Context . The early stages of planet formation, involving dust grain growth and planetesimals formation, remain shrouded in mystery. The analysis of the scattering phase function (SPF) measured in disks surrounding young stars holds great …
DRAGyS -- A comprehensive tool to extract scattering phase functions in protoplanetary disks Open
The early stages of planet formation, involving dust grain growth and planetesimals formation, remain shrouded in mystery. The analysis of the Scattering Phase Function (SPF) measured in disks surrounding young stars holds great potential …
The role of absorption and scattering in shaping ice bands Open
Aims. The James Webb Space Telescope now enables the spectral study of ices with unprecedented sensitivity and angular resolution. Water ice plays a crucial role in the growth of grains and in planetary formation but its spatial distributi…
View article: JWST Imaging of Edge-on Protoplanetary Disks. IV. Mid-infrared Dust Scattering in the HH 30 Disk
JWST Imaging of Edge-on Protoplanetary Disks. IV. Mid-infrared Dust Scattering in the HH 30 Disk Open
We present near- and mid-infrared (IR) broadband imaging observations of the edge-on protoplanetary disk around HH 30 with the James Webb Space Telescope/Near Infrared Camera and the Mid-Infrared Instrument (MIRI). We combine these observa…
View article: JWST Imaging of Edge-on Protoplanetary Disks. IV. Mid-infrared Dust Scattering in the HH 30 disk
JWST Imaging of Edge-on Protoplanetary Disks. IV. Mid-infrared Dust Scattering in the HH 30 disk Open
We present near- and mid-infrared (IR) broadband imaging observations of the edge-on protoplanetary disk around HH 30 with the James Webb Space Telescope/Near Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI). We combine thes…
The grazing angle icy protoplanetary disk PDS 453 Open
PDS 453 is a rare highly inclined disk where the stellar photosphere is seen at grazing incidence on the disk surface. Our goal is take advantage of this geometry to constrain the structure and composition of this disk, in particular the f…
JWST Imaging of Edge-on Protoplanetary Disks. III. Drastic Morphological Transformation Across the Mid-infrared in Oph163131 Open
We present JWST broadband images of the highly inclined protoplanetary disk SSTc2d J163131.2-242627 (Oph163131) from 2.0 to 21 μ m. The images show a remarkable evolution in disk structure with wavelength, quite different from previous JWS…
JWST imaging of edge-on protoplanetary disks. III. Drastic morphological transformation across the mid-infrared in Oph163131 Open
We present JWST broadband images of the highly inclined protoplanetary disk SSTc2d J163131.2-242627 (Oph163131) from 2.0 to 21$μ$m. The images show a remarkable evolution in disk structure with wavelength, quite different from previous JWS…
View article: Multiband polarimetric imaging of HD 34700 with SCExAO/CHARIS
Multiband polarimetric imaging of HD 34700 with SCExAO/CHARIS Open
We present Subaru/SCExAO + CHARIS broad-band (JHK) integral field spectroscopy of HD 34700 A in polarized light. CHARIS has the unique ability to obtain polarized integral field images at 22 wavelength channels in broad-band, as the incomi…
View article: The SPHERE view of the Chamaeleon I star-forming region
The SPHERE view of the Chamaeleon I star-forming region Open
Context . The past few years have seen a revolution in the study of circumstellar disks. New instrumentation in the near-infrared and (sub)millimeter regimes have allowed us to routinely spatially resolve disks around young stars of nearby…
View article: The SPHERE view of the Chamaeleon I star-forming region
The SPHERE view of the Chamaeleon I star-forming region Open
We used VLT/SPHERE to observe 20 systems in the Cha I cloud in polarized scattered light in the near-infrared. We combined the scattered light observations with existing literature data on stellar properties and with archival ALMA continuu…
View article: The importance of the local structure of fractal aggregates
The importance of the local structure of fractal aggregates Open
The pair correlation function, g ( r ), is a fundamental descriptor of the inner structure of fractal aggregates of monomers. It provides a natural tool for studying physical properties involving two-point interaction (e.g. optics of aggre…
JWST Imaging of Edge-on Protoplanetary Disks. I. Fully Vertically Mixed 10 μm Grains in the Outer Regions of a 1000 au Disk Open
Scattered light imaging of protoplanetary disks provides key insights on the geometry and dust properties in the disk surface. Here, we present James Webb Space Telescope (JWST) 2–21 μ m images of a 1000 au radius edge-on protoplanetary di…
JWST Imaging of Edge-on Protoplanetary Disks. II. Appearance of Edge-on Disks with a Tilted Inner Region: Case Study of IRAS04302+2247 Open
We present James Webb Space Telescope imaging from 2 to 21 μ m of the edge-on protoplanetary disk around the embedded young star IRAS04302+2247. The structure of the source shows two reflection nebulae separated by a dark lane. The source …
View article: The polarisation properties of the HD 181327 debris ring
The polarisation properties of the HD 181327 debris ring Open
Context . Polarisation is a powerful remote-sensing tool to study the nature of particles scattering the starlight. It is widely used to characterise interplanetary dust particles in the Solar System and increasingly employed to investigat…
View article: The polarisation properties of the HD 181327 debris ring. Evidence for sub-micron particles from scattered light observations
The polarisation properties of the HD 181327 debris ring. Evidence for sub-micron particles from scattered light observations Open
Polarisation is a powerful remote-sensing tool to study the nature of particles scattering the starlight. It is widely used to characterise interplanetary dust particles in the Solar System and increasingly employed to investigate extrasol…
Insight from laboratory measurements on dust in debris discs Open
Extreme adaptive optics instruments have revealed exquisite details on debris discs, allowing to extract the optical properties of the dust particles such as the phase function, the degree of polarisation and the spectral reflectance. Thes…
Aligned Grains and Scattered Light Found in Gaps of Planet-Forming Disk Open
Polarized (sub)millimeter emission from dust grains in circumstellar disks was initially thought to be due to grains aligned with the magnetic field. However, higher resolution multi-wavelength observations along with improved models found…