A5061483548- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Molecular Spectroscopy and Structure
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Astrophysical Phenomena and Observations
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Gamma-ray bursts and supernovae
- Superconducting and THz Device Technology
- Space Exploration and Technology
- Geophysics and Gravity Measurements
- Advanced Thermodynamic Systems and Engines
- Advanced Combustion Engine Technologies
- Scientific Research and Discoveries
- Advanced Chemical Physics Studies
- Particle Detector Development and Performance
- Planetary Science and Exploration
- Nuclear Physics and Applications
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
Ashikaga University
2022-2025
National Astronomical Observatory of Japan
2018-2023
Ibaraki University
2012-2020
National Institutes of Natural Sciences
2018-2019
The University of Tokyo
2010-2012
Institute of Astronomy
2009-2011
Tokyo University of Science
2009-2010
The Graduate University for Advanced Studies, SOKENDAI
2007-2008
Tokyo Institute of Technology
1995-2005
Astronomical Observatory
2005
We present a new method to constrain the grain size in protoplanetary disks with polarization observations at millimeter wavelengths. If dust grains are grown comparable wavelengths, expected have large scattering opacity and thus continuum emission is be polarized due self-scattering. perform 3D radiative transfer calculations estimate degree for having radial Gaussian-like surface density distributions, which been recently discovered. The maximum set $100 {\rm~\mu m}$ observing wavelength...
Planets form and obtain their compositions in dust gas-rich disks around young stars, the outcome of this process is intimately linked to disk chemical properties. The distributions molecules across regulate elemental planets, including C/N/O/S ratios metallicity (O/H C/H), as well access water prebiotically relevant organics. Emission from also encodes information on ionization levels, temperature structures, kinematics, gas surface densities, which are all key ingredients evolution planet...
Here we present high resolution (15-24 au) observations of CO isotopologue lines from the Molecules with ALMA on Planet-forming Scales (MAPS) Large Program. Our analysis employs $^{13}$CO and C$^{18}$O ($J$=2-1), (1-0), C$^{17}$O (1-0) line five protoplanetary disks. We retrieve gas density distributions, using three independent methods: (1) a thermo-chemical modeling framework based data, broadband spectral energy distribution, mm-continuum emission; (2) an empirical temperature...
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,...
We present a new Subaru/HiCIAO high-contrast H-band polarized intensity (PI) image of nearby transitional disk associated with TW Hydrae. The scattered light from the was detected 0.2" to 1.5" (11 - 81 AU) and PI shows clear axisymmetric depression in at ~ 0.4" (~ 20 central star, similar 80 AU gap previously reported HST images. Azimuthal profile also beyond is almost axisymmetric. discuss two possible scenarios explaining origin depression: 1) structure may exist star because shallow slope...
Abstract We report on ALMA observations of the dust continuum, and $^{13}\textrm {CO} (J=3-2), \textrm {and} {C}^{18} \textrm{O} (J=3-2)$ line emission toward a gapped protoplanetary disk around HD 142527. The outer horseshoe-shaped shows strong azimuthal asymmetry in continuum with ratio $\sim 30$ to 1 at 336 GHz between northern peak southwestern minimum. In addition, maximum brightness temperature 24K its area is exceptionally high 160 au from star. To evaluate surface density this...
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 present the polarization observations toward circumstellar disk around HD 142527 by using Atacama Large Millimeter/submillimeter Array (ALMA) at frequency of 343 GHz. The beam size is $0.51 " \times 0.44 "$, which corresponds to spatial resolution $\sim$ 71 $\times$ 62 AU. polarized intensity displays a ring-like structure with peak located on east side fraction $P= 3.26 \pm 0.02$ %, different from continuum emission northeast region. significantly weaker where 0.220 0.010$ %. vectors are...
Abstract The Molecules with ALMA at Planet-forming Scales Large Program (MAPS LP) surveyed the chemical structures of five protoplanetary disks across more than 40 different spectral lines high angular resolution (0.″15 and 0.″30 beams for Bands 6 3, respectively) sensitivity (spanning 0.3–1.3 mJy beam −1 0.4–1.9 respectively). In this article, we describe multistage workflow—built around CASA tclean image deconvolution procedure—that used to generate core data product MAPS LP:...
The Molecules with ALMA at Planet-forming Scales (MAPS) Large Program provides a unique opportunity to study the vertical distribution of gas, chemistry, and temperature in protoplanetary disks around IM Lup, GM Aur, AS 209, HD 163296, MWC 480. By using asymmetry molecular line emission relative disk major axis, we infer height ($z$) above midplane as function radius ($r$). Using this method, measure emitting surfaces for suite CO isotopologues, HCN, C$_2$H. We find that $^{12}$CO traces...
The Molecules with ALMA at Planet-forming Scales (MAPS) Large Program provides a detailed, high resolution (${\sim}$10-20 au) view of molecular line emission in five protoplanetary disks spatial scales relevant for planet formation. Here, we present systematic analysis chemical substructures 18 lines toward the MAPS sources: IM Lup, GM Aur, AS 209, HD 163296, and MWC 480. We identify more than 200 substructures, which are found nearly all radii where is detected. A wide diversity radial...
Constraining dust properties of planet-forming disks via high angular resolution observations is fundamental to understanding how solids are trapped in substructures and growth may be favored or accelerated therein. We use ALMA continuum the Molecules with at Planet-forming Scales (MAPS) explore a large parameter space constrain radial distribution solid mass maximum grain size each disk, including excluding scattering. In nonscattering model, surface density profiles decrease from inner...
The elemental composition of the gas and dust in a protoplanetary disk influences compositions planets that form it. We use Molecules with ALMA at Planet-forming Scales (MAPS) data to constrain locations potentially forming planets. abundances are inferred by comparing source-specific gas-grain thermochemical models, variable C/O ratios small-grain abundances, from DALI code CO C2H column densities derived high-resolution observations disks AS 209, HD 163296, MWC 480. Elevated (~2.0), even...
We report high-resolution (0.07 arcsec) near-infrared polarized intensity images of the circumstellar disk around star 2MASS J16042165-2130284 obtained with HiCIAO mounted on Subaru 8.2 m telescope. present our $H$-band data, which clearly exhibits a resolved, face-on large inner hole for first time at infrared wavelengths. detect centrosymmetric polarization pattern in material as has been observed other disks. Elliptical fitting gives semimajor axis, semiminor and position angle (P.A.) 63...
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 The mechanisms causing millimeter-wave polarization in protoplanetary disks are under debate. To disentangle the mechanisms, we observe disk around HL Tau at 3.1 mm with Atacama Large Millimeter/submillimeter Array (ALMA), which had detected CARMA 1.3 mm. We successfully detect ring-like azimuthal polarized emission This indicates that dust grains aligned major axis being direction, is consistent theory of radiative alignment elongated grains, where perpendicular to radiation flux....
Aims. We derive physical properties such as the optical depths and column densities of 13CO C18O to investigate relationship between far ultraviolet (FUV) radiation abundance ratios C18O.
The formation scenario of a gapped disk, i.e., transitional and its asymmetry is still under debate. Proposed scenarios such as disk–planet interaction, photoevaporation, grain growth, anticyclonic vortex, eccentricity, their combinations would result in different radial distributions the gas small (sub-μm size) large (millimeter dust grains well asymmetric structures disk. Optical/near-infrared (NIR) imaging observations (sub-)millimeter interferometry can trace grains, respectively;...
The millimeter-wave polarization of the protoplanetary disk around HL Tau has been interpreted as emission from elongated dust grains aligned with magnetic field in disk. However, self-scattering thermal may also explain observed polarization. In this paper, we report a modeling self-polarization. Dust are assumed to be spherical and have power-law size distribution. We change maximum grain fixed composition model find reproduce signature. that direction vectors degree can explained...
Abstract The origin of polarized emission from protoplanetary disks is uncertain. Three mechanisms have been proposed for this emission: grain alignment with magnetic fields, radiation gradients, and self-scattering thermal dust emission. Aiming to observationally identify the polarization mechanisms, we present ALMA observations 0.87 mm continuum toward circumstellar disk around HD 142527 high spatial resolution. We confirm that vectors in northern region are consistent self-scattering....
Sulfur-bearing molecules play an important role in prebiotic chemistry and planet habitability. They are also proposed probes of chemical ages, elemental C/O ratio, grain processing. Commonly detected diverse astrophysical objects, including the Solar System, their distribution remain, however, largely unknown planet-forming disks. We present CS ($2-1$) observations at $\sim0."3$ resolution performed within ALMA-MAPS Large Program toward five disks around IM Lup, GM Aur, AS 209, HD 163296,...
Abstract The concentric gaps and rings commonly observed in protoplanetary disks millimeter continuum emission have lent the impression that planet formation generally proceeds within orderly, isolated systems. While deep observations of spatially resolved molecular been comparatively limited, they are increasingly suggesting some interact with their surroundings while is underway. We present an analysis complex features identified around GM Aur 12 CO J = 2 − 1 images at a spatial resolution...
The precursors to larger, biologically-relevant molecules are detected throughout interstellar space, but determining the presence and properties of these during planet formation requires observations protoplanetary disks at high angular resolution sensitivity. Here we present 0.3" HC$_3$N, CH$_3$CN, $c$-C$_3$H$_2$ in five observed as part Molecules with ALMA Planet-forming Scales (MAPS) Large Program. We robustly detect all four (GM Aur, AS 209, HD 163296 MWC 480) tentative detections...
Abstract High spatial resolution CO observations of midinclination (≈30°–75°) protoplanetary disks offer an opportunity to study the vertical distribution emission and temperature. The asymmetry line relative disk major axis allows for a direct mapping height above midplane, optically thick, spatially resolved in LTE, intensity is measure local gas Our analysis Atacama Large Millimeter/submillimeter Array archival data yields surfaces, dynamically constrained stellar host masses, atmosphere...