A5064085516- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Spacecraft and Cryogenic Technologies
- Renal Transplantation Outcomes and Treatments
- Organ Transplantation Techniques and Outcomes
- Inflammatory mediators and NSAID effects
- Natural product bioactivities and synthesis
- Renal and Vascular Pathologies
- Pediatric Urology and Nephrology Studies
- Biological Stains and Phytochemicals
- Space Exploration and Technology
- Organ Donation and Transplantation
- Metabolism and Genetic Disorders
- Xenotransplantation and immune response
- Lymphatic Disorders and Treatments
- Urinary Tract Infections Management
- Pregnancy and Medication Impact
- Cancer Immunotherapy and Biomarkers
- Proteoglycans and glycosaminoglycans research
- Vascular Malformations and Hemangiomas
- Advanced Thermodynamic Systems and Engines
- Natural Products and Biological Research
Tokyo Institute of Technology
2024
Ibaraki University
2021-2023
The University of Tokyo
2018-2022
University of Szczecin
2016-2020
Institute of Physics
2016-2020
Kavli Institute for the Physics and Mathematics of the Universe
2020
Hokkaido University
1994-2016
Asahikawa City Hospital
1998-2009
Kushiro Rosai Hospital
2007
Sapporo City General Hospital
1992
A large planet orbiting a star in protoplanetary disk opens density gap along its orbit due to the strong disk-planet interaction and migrates with disk. It is expected that ideal case, gap-opening at viscous drift speed, which referred as type II migration. However, recent hydrodynamic simulations have shown general, not locked evolution. new physical model required explain migration speed of such planet. For this reason, we re-examined disk, by carrying out two-dimensional wide parameter...
A giant planet embedded in a protoplanetary disk forms gap. An analytic relationship among the gap depth, mass $M_{p}$, aspect ratio $h_p$, and viscosity $\alpha$ has been found recently, depth can be written terms of single parameter $K= (M_{p}/M_{\ast})^2 h_p^{-5} \alpha^{-1}$. We discuss how observed features used to constrain and/or parameters based on formula for depth. The constraint is critical determining so combination observations temperature image provide mass. apply HL~Tau...
A giant planet creates a gap in protoplanetary disk, which might explain the observed gaps disks. The width and depth of depend on mass disk properties. We have performed two--dimensional hydrodynamic simulations for various masses, aspect ratios viscosities, to obtain an empirical formula width. is proportional square root mass, -3/4 power ratio -1/4 viscosity. This enables us estimate embedded from gap. applied around HL~Tau, assuming that each by ALMA observations produced planets,...
The gap formation induced by a giant planet is important in the evolution of and protoplanetary disc. We examine with new formulation one-dimensional viscous discs which takes into account deviation from Keplerian disc rotation due to steep gradient surface density. This enables us naturally include Rayleigh stable condition for rotation. It found that derivation promotes radial angular momentum transfer makes shallower than case. For deep gaps, this shallowing effect becomes significant...
ABSTRACT We report ∼3 au resolution imaging observations of the protoplanetary disk around TW Hya at 145 and 233 GHz with Atacama Large Millimeter/submillimeter Array. Our revealed two deep gaps (∼25%–50%) 22 37 shallower (a few percent) 6, 28, 44 au, as recently reported by Andrews et al. The central hole a radius was also marginally resolved. most remarkable finding is that spectral index between bands 4 6 peaks gap. derived power-law dust opacity ∼1.7 gap decreases toward center to ∼0....
We report the first detection of a gap and ring in 336 GHz dust continuum emission from protoplanetary disk around TW Hya, using Atacama Large Millimeter/Submillimeter Array (ALMA). The are located at 25 41 au central star, respectively, associated with CO snow line ~30 au. has radial width less than 15 mass deficit more 23%, taking into account that observations limited to an angular resolution ~15 In addition, 13CO C18O J = 3 - 2 lines show decrement throughout disk, down ~10 au,...
Abstract A giant planet embedded in a protoplanetary disk creates gap. This process is important for both theory and observation. Using results of survey wide parameter range with two-dimensional hydrodynamic simulations, we constructed an empirical formula the gap structure (i.e., radial surface density distribution), which can reproduce width depth obtained by simulations. enables us to judge whether observed likely be caused or not. The propagation waves launched closely connected...
Context . The past few years have seen a revolution in the study of circumstellar disks. New instrumentation near-infrared and (sub)millimeter regimes allowed us to routinely spatially resolve disks around young stars nearby star-forming regions. As result, we found that substructures with scales ~10 au are common. We also revealed zoo different morphologies, sizes, luminosities is as complex diversity architectures evolved exoplanet systems. Aims disk evolutionary trends they appear...
Abstract The mass and semimajor axis distribution of gas giants in exoplanetary systems obtained by radial velocity surveys shows that super-Jupiter-mass planets are piled up at ≳1 au, while Jupiter/sub-Jupiter-mass broadly distributed from ∼0.03 au to beyond 1 au. This feature has not been explained theoretical predictions. In order reconcile this inconsistency, we investigate evolution with a new type II migration formula Kanagawa et al., comparing the migration, growth timescales giants,...
Coronagraphic imagery of the circumstellar disk around HD 169142 in H-band polarized intensity (PI) with Subaru/HiCIAO is presented. The emission scattered by dust particles at surface 0.2" <= r 1.2", or 29 174 AU, successfully detected. azimuthally-averaged radial profile PI shows a double power-law distribution, which PIs r=29-52 AU and r=81.2-145 respectively show r^{-3}-dependence. These two regions are connected smoothly transition zone (TZ), exhibiting an apparent gap r=40-70 AU. inner...
The total amount of dust (or "metallicity") and the distribution in protoplanetary disks are crucial for planet formation. Dust grains radially drift due to gas--dust friction, gas is affected by feedback from grains. We investigate effects on viscous evolution gas, taking into account vertical settling. pushes outward. When small dust-to-gas mass ratio much smaller than unity, radial velocity reduced effect but still drifts inward. sufficiently large or piled-up, so effective that forces...
Aims. The protoplanetary disk around HL Tau is the youngest candidate of planet formation known to date, and it still embedded in a protostellar envelope with size thousands au. In this work, we study gas kinematics its possible influence on disk.
Abstract We present molecular line observations of 13 CO and C 18 O J = 3 − 2, CN N CS 7 6 lines in the protoplanetary disk around TW Hya at a high spatial resolution ∼9 au (angular 0.″15), using Atacama Large Millimeter/Submillimeter Array. A possible gas gap is found deprojected radial intensity profile integrated radius ∼58 au, slightly beyond location au-scale dust clump ∼52 which resembles predictions from hydrodynamic simulations planet–disk interaction. In addition, we construct...
When a planet forms deep gap in protoplanetary disk, dust grains cannot pass through the gap. As consequence, density of can increase up to same level gas at outer edge. The feedback on from drifting is not negligible, such dusty region. We carried out two-dimensional two-fluid (gas and dust) hydrodynamic simulations. found that when radial flow across halted, broad ring be formed because diffusion grains. minimum mass form consistent with pebble-isolation mass, parameter range our good...
We conducted a Phase II trial to investigate the efficacy of combined therapy with meloxicam, cyclooxygenase-2 inhibitor and natural interferon (IFN)-alpha in renal cell carcinoma patients distant metastasis.The subjects this study were untreated who diagnosed from results imaging or pathological studies had measurable lesions according Response Evaluation Criteria Solid Tumors (RECIST). Patients could be enrolled irrespective whether nephrectomy been performed. Treatment involved...
Abstract A giant planet embedded in a protoplanetary disk opens gap by tidal interaction, and properties of the strongly depend on planetary mass parameters. Many numerical simulations this process have been conducted, but detailed analysis formation super-Jupiter-mass not thoroughly conducted. We performed two-dimensional hydrodynamic examined eccentricity gap. When is massive, radial motion gas excited, causing gap’s outer edge to increase. Our showed that critical for eccentric was ∼ 3 M...
Abstract We report the detection of an excess in dust continuum emission at 233 GHz (1.3 mm wavelength) protoplanetary disk (PPD) around TW Hya revealed through high-sensitivity observations ∼3 au resolution with Atacama Large Millimeter/submillimeter Array. The sensitivity image has been improved by a factor 3 regard to that our previous cycle observations. overall structure is mostly axisymmetric, and there are apparent gaps 25 41 as previously reported. most remarkable new finding few...
Abstract When two planets are born in a protoplanetary disk, they may enter into mean-motion resonance as consequence of convergent planetary migration. The formation resonances is important for understanding how systems shaped disk environments. Motivated by recent progress the comprehension migration partial gap-opening planets, we have investigated orbital evolution planet pairs wide range masses and properties with aim to find out when capture likely happen. Using formula timescale...
We present a high-resolution (2.5 au) multiband analysis of the protoplanetary disk around TW Hya using ALMA long baseline data at Bands 3, 4, 6, and 7. aim to reconstruct high-sensitivity millimeter continuum image revisit spectral index distribution. The imaging is performed by combining new 4 6 with available archive data. Two methods are employed images; multi-frequency synthesis (MFS) fiducial image-oriented method, where each band imaged separately frequency dependence fitted pixel...
Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission the disk around WW Cha. The image shows a smooth structure with faint (low-contrast) ring, extending from ∼40 au to ∼70 au, not accompanied by any gap. constructed simple model fit visibility observed data using Markov Chain Monte Carlo (MCMC) method and found that bump (we call ring without gap bump) has two peaks at 40 70 au. residual map between observation indicates...
GW Ori is a hierarchical triple system which has rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12CO J=2-1 molecular gas emission the For first time, we identify three rings in disk at ~46, 188, 338 AU, with estimated mass ~70-250 Earth masses, respectively. To our knowledge, outer ring largest ever found protoplanetary disks. use visibility modelling to show that misaligned parts innermost eccentric. The...
We used VLT/SPHERE to observe 20 systems in the Cha I cloud polarized scattered light near-infrared. combined observations with existing literature data on stellar properties and archival ALMA continuum study trends system age dust mass. also connected resolved near-infrared spectral energy distributions of systems. In 13 included this we detected signals from circumstellar dust. For CR Cha, CT CV SY SZ VZ present first detailed descriptions disks light. The found typically smooth or faint...
Abstract Planetary migration due to disk–planet interaction is one of the most important processes determining architecture planetary systems. A sufficiently massive planet forms a density gap, and migrates together with gap. By carrying out two-dimensional two-fluid (gas dust grains) hydrodynamic simulations, we investigated effects feedback on gap-opening planet, which has not been considered in previous studies. We found that gas surface at outer edge gap becomes smaller feedback, thus...
Abstract A planet is formed within a protoplanetary disk. Recent observations have revealed substructures such as gaps and rings, which may indicate forming planets the Due to disk–planet interaction, migrates disk, can affect shape of planet-induced gap. In this paper, we investigate effects fast inward migration on gap shape, by carrying out hydrodynamic simulations. We found that when timescale shorter than gap-opening, orbital radius shifted compared radial location also scaling relation...