Tohoku University · 물리·천문학
Ryo Tazaki 교수의 연구실은 원형성과 구조가 복잡한 미세먼지 입자, 특히 프로플란네이터 디스크 내에서 형성되는 다공성 먼지 응집체의 광학적 성질과 기체역학적 거동을 중심으로 연구를 진행합니다. 주로 near-infrared 산란광과 극화 관측을 기반으로 한 정밀한 복사전달 시뮬레이션과 T-매트릭스 방법을 활용해, 먼지 입자의 크기, 다공성, 형상 등 물리적 특성이 천체 관측 결과에 어떻게 영향을 주는지 규명하고자 합니다. 특히, ALMA 등 현대 천체망원경의 관측 데이터와의 비교를 통해 초기 행성계에서 먼지의 성장 메커니즘을 해석하는 데 초점을 맞추고 있습니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Abstract We apply the theory of radiative torque (RAT) alignment for studying protoplanetary disks around a T-Tauri star and perform 3D radiative transfer calculations to provide the expected maps of polarized radiation to be compared with observations, such as with ALMA. We revisit the issue of grain alignment for large grains expected in the protoplanetary disks and find that mm-sized grains at the midplane do not align with the magnetic field since the Larmor precession timescale for such lar
ABSTRACT In protoplanetary disks, micron-sized dust grains coagulate to form highly porous dust aggregates. Because the optical properties of these aggregates are not completely understood, it is important to investigate how porous dust aggregates scatter light. In this study, the light scattering properties of porous dust aggregates were calculated using a rigorous method, the T -matrix method, and the results were then compared with those obtained using the Rayleigh–Gans–Debye (RGD) theory and
We study scattered light properties of protoplanetary discs at near-infrared wavelengths for various dust size and structure by performing radiative transfer simulations. We show that different dust structures might be probed by measuring disk polarisation fraction as long as the dust radius is larger than the wavelength. When the radius is larger than the wavelength, disc scattered light will be highly polarised for highly porous dust aggregates, whereas more compact dust structure tends to sho
Abstract Despite rapidly growing disk observations, it remains a mystery what primordial dust aggregates look like and what the physical and chemical properties of their constituent grains (monomers) are in young planet-forming disks. Confrontation of models with observations to answer this mystery has been a notorious task because we have to abandon a commonly used assumption, perfectly spherical grains, and take into account particles with complex morphology. In this Letter, we present the fir
Context. The size of the constituent particles (monomers) of dust aggregates is one of the most uncertain parameters directly affecting collisional growth of aggregates in planet-forming disks. Despite its importance, the monomer size has not yet been meaningfully constrained by disk observations. Aims. We attempt to derive the monomer size from optical and near-infrared (IR) polarimetric observations of planet-forming disks. Methods. We performed a comprehensive parameter survey on the degree o
ABSTRACT In protoplanetary discs and planetary atmospheres, dust grains coagulate to form fractal dust aggregates. The geometric cross-section of these aggregates is a crucial parameter characterizing aerodynamical friction, collision rates, and opacities. However, numerical measurements of the cross-section are often time consuming as aggregates exhibit complex shapes. In this study, we derive a novel analytic expression for geometric cross-sections of fractal aggregates. If an aggregate consis
Abstract We study the 3 μ m scattering feature of water ice detected in the outer disk of HD 142527 by performing radiative transfer simulations. We show that an ice mass abundance at the outer disk surface of HD 142527 is much lower than estimated in a previous study. It is even lower than inferred from far-infrared ice observations, implying ice disruption at the disk surface. Next, we demonstrate that a polarization fraction of disk-scattered light varies across the ice-band wavelengths depen
Abstract 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 observations with archival optical/near-IR scattered light images obtained with the Hubble Space Telescope and a millimeter-wavelength dust continuum image obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) with the highest spatial resoluti
Abstract Water ice has a strong spectral feature at a wavelength of approximately 3 μ m, which plays a vital role in our understanding of the icy universe. In this study, we investigate the scattering polarization of this water-ice feature. The linear polarization degree of light scattered by micron-sized icy grains is known to be enhanced at the ice band; however, the dependence of this polarization enhancement on various grain properties is unclear. We find that the enhanced polarization at th
This is a reproduction package for the paper "The Water-ice Feature in Near-infrared Disk-scattered Light around HD 142527: Micron-sized Icy Grains Lifted up to the Disk Surface?" by Tazaki et al. (2021). In this repository, you will find the data files used to make figures in the paper. Source codes and scripts are included as well.
This is a reproduction package for the paper "The Water-ice Feature in Near-infrared Disk-scattered Light around HD 142527: Micron-sized Icy Grains Lifted up to the Disk Surface?" by Tazaki et al. (2021). In this repository, you will find the data files used to make figures in the paper. Source codes and scripts are included as well.
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 these observations with archival optical/near-IR scattered light images obtained with the Hubble Space Telescope (HST) and a millimeter-wavelength dust continuum image obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) with the highest spatial re
