194 citations · 1.3k across the 29 of their papers we have counts for
29 papers
Early Planet Formation in Embedded Disks (eDisk). XVIII. Indication of a possible spiral structure in the dust-continuum emission of the protostellar disk around IRAS 16544-1604 in CB 68
Sanemichi Z. Takahashi, Shigehisa Takakuwa, Ryosuke Nakanishi +11
We performed numerical simulations along with radiative transfer calculations to reproduce an intriguing asymmetric shoulder feature in the dust-continuum emission of the protostel…
Predicting dust temperature from molecular line data using machine learning
Tenta Dougome, Yoshito Shimajiri, Kazuya Saigo +4
We conducted experiments with machine learning techniques to construct dust temperature maps from the CO isotopologue molecular line data in the Orion A molecular cloud. In the cla…
On Secular Gravitational Instability in Vertically Stratified Disks
Ryosuke T. Tominaga, Shu-ichiro Inutsuka, Sanemichi Z. Takahashi
Secular gravitational instability (GI) is one promising mechanism for explaining planetesimal formation. The previous studies on secular GI utilized a razor-thin disk model and der…
ALMA Band 6 high-resolution observations of the transitional disk around SY Cha
Ryuta Orihara, Munetake Momose, Takayuki Muto +10
In this study, we reported the results of high-resolution (0.14 arcsec) Atacama Large Millimeter/submillimeter Array (ALMA) observations of the 225 GHz dust continuum and CO molecu…
Planetesimal formation by the gravitational instability of dust ring structures
Sanemichi Z. Takahashi, Eiichiro Kokubo, Shu-ichiro Inutsuka
We investigate the gravitational instability (GI) of dust-ring structures and the formation of planetesimals by their gravitational collapse. The normalized dispersion relation of…
ALMA High-resolution Multiband Analysis for the Protoplanetary Disk around TW Hya
Takashi Tsukagoshi, Hideko Nomura, Takayuki Muto +10
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. We aim to reconstruct a hig…
ALMA observation of the protoplanetary disk around WW Cha: faint double-peaked ring and asymmetric structure
Kazuhiro D. Kanagawa, Jun Hashimoto, Takayuki Muto +13
We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission of the disk around WW Cha. The dust continuum image shows a smooth dis…
Secular Gravitational Instability of Drifting Dust in Protoplanetary Disks: Formation of Dusty Rings without Significant Gas Substructures
Ryosuke T. Tominaga, Sanemichi Z. Takahashi, Shu-ichiro Inutsuka
Secular gravitational instability (GI) is one of the promising mechanisms for creating annular substructures and planetesimals in protoplanetary disks. We perform numerical simulat…
SCExAO/CHARIS High-Contrast Imaging of Spirals and Darkening Features in the HD 34700 A Protoplanetary Disk
Taichi Uyama, Thayne Currie, Valentin Christiaens +27
We present Subaru/SCExAO+CHARIS broadband (-band) integral field spectroscopy of HD 34700 A. CHARIS data recover HD 34700 A's disk ring and confirm multiple spirals discovered…
GW Ori: Interactions Between a Triple-star System and its Circumtriple Disk in Action
Jiaqing Bi, Nienke van der Marel, Ruobing Dong +17
GW Ori is a hierarchical triple system which has a rare circumtriple disk. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and…
The detection of dust gap-ring structure in the outer region of the CR Cha protoplanetary disk
Seongjoong Kim, Sanemichi Takahashi, Hideko Nomura +13
We observe the dust continuum at 225 GHz and CO isotopologue (12CO, 13CO, and C18O) J=2-1 emission lines toward the CR Cha protoplanetary disk using the Atacama Large Millimeter/Su…
Revised description of dust diffusion and a new instability creating multiple rings in protoplanetary disks
Ryosuke T. Tominaga, Sanemichi Z. Takahashi, Shu-ichiro Inutsuka
Various instabilities have been proposed as a promising mechanism to accumulate dust. Moreover, some of them are expected to lead to the multiple-ring structure formation and the p…
Discovery of an au-scale excess in millimeter emission from the protoplanetary disk around TW Hya
Takashi Tsukagoshi, Takayuki Muto, Hideko Nomura +10
We report the detection of an excess in dust continuum emission at 233~GHz (1.3~mm in wavelength) in the protoplanetary disk around TW~Hya revealed through high-sensitivity observa…
Gravitational stability and fragmentation condition for discs around accreting supermassive stars
Ryoki Matsukoba, Sanemichi Z. Takahashi, Kazuyuki Sugimura +1
Supermassive stars (SMSs) with mass are promising candidates for the origin of supermassive black holes observed at redshift . They are suppos…
Structure Formation in a Young Protoplanetary Disk by a Magnetic Disk Wind
Sanemichi Z. Takahashi, Takayuki Muto
Structure formation in young protoplanetary disks is investigated using a one-dimensional model including the formation and the evolution of disks. Recent observations with ALMA fo…
Non-linear Development of Secular Gravitational Instability in Protoplanetary Disks
Ryosuke T. Tominaga, Shu-ichiro Inutsuka, Sanemichi Z. Takahashi
We perform non-linear simulation of secular gravitational instability (GI) in protoplanetary disks that has been proposed as a mechanism of the planetesimal formation and the multi…
Primordial protostars accreting beyond the -limit: radiation effect around the star-disk boundary
Sanemichi Z. Takahashi, Kazuyuki Omukai
We consider whether the maximum mass of first stars is imposed by the protostellar spin, i.e., by the so-called -limit, which requires the sum of the radiation and centrifugal…
Orbital Evolution of Moons in Weakly Accreting Circumplanetary Disks
Yuri I. Fujii, Hiroshi Kobayashi, Sanemichi Z. Takahashi +1
We investigate the formation of hot and massive circumplanetary disks (CPDs) and the orbital evolution of satellites formed in these disks. Because of the comparatively small size-…
Evolution of an Accretion Disk in Binary Black Hole Systems
Shigeo S. Kimura, Sanemichi Z. Takahashi, Kenji Toma
We investigate evolution of an accretion disc in binary black hole (BBH) systems and possible electromagnetic counterparts of the gravitational waves from mergers of BBHs. Perna et…
From Birth to Death of Protoplanetary Disks: Modeling Their Formation, Evolution, and Dispersal
Shigeo S. Kimura, Masanobu Kunitomo, Sanemichi Z. Takahashi
Formation, evolution, and dispersal processes of protoplanetary disks are investigated and the disk lifetime is estimated. Gravitational collapse of a pre-stellar core forms both a…
An Origin of Multiple Ring Structure and Hidden Planets in HL Tau: A Unified Picture by Secular Gravitational Instability
Sanemichi Z. Takahashi, Shu-ichiro Inutsuka
Recent ALMA observation has revealed multiple ring structures formed in a protoplanetary disk around HL Tau. Prior to the ALMA observation of HL Tau, theoretical analysis of secula…
The Origin of the Rotation Profiles in Star Forming Clouds
Sanemichi Z. Takahashi, Kengo Tomida, Masahiro N. Machida +1
Angular momentum distribution and its redistribution are of crucial importance in formation and evolution of circumstellar disks. Many molecular line observations toward young stel…
A revised condition for self-gravitational fragmentation of protoplanetary disks
Sanemichi Z. Takahashi, Yusuke Tsukamoto, Shu-ichiro Inutsuka
Fragmentation of protoplanetary disks due to gravitational instabilities is a candidate of a formation mechanism of binary stars, brown dwarfs, and gaseous giant planets. The condi…
Significant Gas-to-Dust Ratio Asymmetry and Variation in the Disk of HD 142527 and the Indication of Gas Depletion
Takayuki Muto, Takashi Tsukagoshi, Munetake Momose +14
We investigate the dust and gas distribution in the disk around HD 142527 based on ALMA observations of dust continuum, 13CO(3-2), and C18O(3-2) emission. The disk shows strong azi…