Gas Accretion from a Circumbinary Disk (2009)
Hanawa, Tomoyuki, Ochi, Yasuhiro, Ando, Koichi
A new computational scheme is developed to study gas accretion from a circumbinary disk. The scheme decomposes the gas velocity into two components one of which denotes the Keplerian rotation and the...
Critical Accretion Rate for Triggered Star Formation (2008)
Hanawa, Tomoyuki, Soeda, Akihito
We have reexamined the similarity solution for a self-gravitating isothermal gas sphere and examined implication to star formation in a turbulent cloud. When parameters are adequately chosen, the...
Three Dimensional Magnetohydrodynamical Simulations of Core Collapse Supernova (2008)
Mikami, Hayato, Sato, Yuji, Matsumoto, Tomoaki, Hanawa, Tomoyuki
We show three-dimensional magnetohydrodynamical simulations of core collapse supernova in which the progenitor has magnetic fields inclined to the rotation axis. The simulations employed a simple...
Fumitaka Nakamura Faculty, Fumitaka Nakamura, Tomoyuki Hanawa, Tomoaki Matsumoto
We followed fragmentation of magnetized filamentary clouds and formation of disks with two-dimensional numerical simulations. A filamentary cloud with longitudinal magnetic fields fragments to form...
Non-axisymmetric Evolution of Dynamically Contracting Disks and Formation of Binary Stars (2007)
Fumitakanakamura Laboratory Of, Tomoyuki Hanawa
Using two-dimensional hydrodynamical simulations, we followed the evolution of a dynamically-collapsing, rotating disk permeated by vertical magnetic field. As a model of a disk, the similarity...
Fumitaka Nakamura Faculty, Fumitaka Nakamura, Tomoyuki Hanawa, Tomoaki Matsumoto
We followed fragmentation of magnetized filamentary clouds and formation of disks with two-dimensional numerical simulations. A filamentary cloud with longitudinal magnetic fields fragments to form...
Fumitakanakamura Faculty Of, Tomoyuki Hanawa, Tomoaki Matsumoto
Wefollowed fragmentation of magnetized filamentary clouds and formation of disks with two-dimensional numerical simulations. A filamentary cloud with longitudinal magnetic fields fragments to form...
Gravitational Collapse of a Rotating Cloud to Form Star and Disk System (2007)
Tomoyuki Hanawa, Tomoaki Matsumoto
Wepresenttwo-dimensional numerical simulations of gravitational collapse of a rotating cloud. The collaping cloud forms a dynamically contracting disk. The disk structure can be well reproduced by a...
Formation of a Dynamically Contracting Protostellar Disk (2007)
We present similarity solutions that describe the runaway collapse of a rotating isothermal cloud and its subsequent inside-out collapse. During the runaway collapse, the surface density of the disk...
Non-axisymmetric Evolution of Dynamically Contracting Disks and Formation of Binary Stars (2007)
Fumitaka Nakamura, Tomoyuki Hanawa
Using two-dimensional hydrodynamical simulations, we followed the evolution of a dynamically-collapsing, rotating disk permeated by vertical magnetic field. As a model of a disk, the similarity...
Gravitational Collapse of a Rotating Cloud to Form Star and Disk System (2007)
Tomoyuki Hanawa, Tomoaki Matsumoto, Fumitaka Nakamura
We present two-dimensional numerical simulations of gravitational collapse of a rotating cloud. The collaping cloud forms a dynamically contracting disk. The disk structure can be well reproduced by...
Non-axisymmetric Evolution of Dynamically Contracting Disks and Formation of Binary Stars (2007)
Fumitaka Nakamura, Tomoyuki Hanawa
Using two-dimensional hydrodynamical simulations, we followed the evolution of a dynamically-collapsing, rotating disk permeated by vertical magnetic field. As a model of a disk, the similarity...
EFFECTS OF THE ALFV EN WAVEON THE GRAVITATIONAL INSTABILITY IN THE INTERSTELLAR MEDIUM (2007)
Abstract. We present a numerical simulation on the gravitational collapse of the interstellar gas in which the Alfv'en wave propagates with large amplitude. The Alfv'en wave has an...
Fumitaka Nakamura, Tomoyuki Hanawa, Kohji Tomisaka
We study dynamical collapse of isothermal magnetized clouds with two-dimensional axisymmetric numerical simulations. As a model of the cloud, we consider an infinitely long filamentary cloud with...
Evolution of Rotating Molecular Cloud Core with Oblique Magnetic Field (2006)
Machida, Masahiro N., Matsumoto, Tomoaki, Hanawa, Tomoyuki, Tomisaka, Kohji
We studied the collapse of rotating molecular cloud cores with inclined magnetic fields, based on three-dimensional numerical simulations.The numerical simulations start from a rotating Bonnor-Ebert...
Collapse and Fragmentation of Rotating Magnetized Clouds. I. Magnetic Flux - Spin Relation (2005)
Machida, Masahiro N, Matsumoto, Tomoaki, Tomisaka, Kohji, Hanawa, Tomoyuki
We discuss evolution of the magnetic flux density and angular velocity in a molecular cloud core, on the basis of three-dimensional numerical simulations, in which a rotating magnetized cloud...
Machida, Masahiro N, Matsumoto, Tomoaki, Hanawa, Tomoyuki, Tomisaka, Kohji
Subsequent to Paper I, the evolution and fragmentation of a rotating magnetized cloud are studied with use of three-dimensional MHD nested-grid simulations. After the isothermal runaway collapse, an...
3次元輻射磁気流体力学シミュレーションによる初期原始星進化の研究 (2004)
花輪, 知幸, ハナワ, トモユキ, Hanawa, Tomoyuki
平成14年度～平成15年度科学研究費補助金(基盤研究(B)(1))研究成果報告書
3次元輻射磁気流体力学シミュレーションによる初期原始星進化の研究 (2004)
花輪, 知幸, ハナワ, トモユキ, Hanawa, Tomoyuki
平成14年度～平成15年度科学研究費補助金(基盤研究(B)(1))研究成果報告書
Accretion of protobinary and evolution of the mass ratio (2004)
Hanawa, Tomoyuki, Ochi, Yasuhiro, Sugimoto, Kanako
Reexaminamos la acrecion en un sistema protobinario mediante simulaciones numericas en dos dimensiones. Consideramos estrellas en orbitas circulares en torno al centro de masa. Suponemos que el ujo...
Matsumoto, Tomoaki, Hanawa, Tomoyuki
The fragmentation of molecular cloud cores a factor of 1.1 denser than the critical Bonnor-Ebert sphere is examined though three-dimensional numerical simulations. A nested grid is employed to...
A Fast Algorithm for Solving the Poisson Equation on a Nested Grid (2002)
Matsumoto, Tomoaki, Hanawa, Tomoyuki
We present a numerical method for solving the Poisson equation on a nested grid. The nested grid consists of uniform grids having different grid spacing and is designed to cover the space closer to...
Stability of Toomre-Hayashi Disk (2000)
Hanawa, Tomoyuki, Saigo, Kazuya, Matsumoto, Tomoaki
We investigate stability of Toomre-Hayashi model for a self-gravitating, rotating gas disk. The rotation velocity, $ v_\phi $, and sound speed, $ c _{\rm s} $, are spatially constant in the model. We...
Growth of a Vortex Mode during Gravitational Collapse Resulting in Type II Supernova (2000)
Hanawa, Tomoyuki, Matsumoto, Tomoaki
We investigate stability of a gravitationally collapsing iron core against non-spherical perturbation. The gravitationally collapsing iron core is approximated by a similarity solution for...
Stability of Dynamically Collapsing Gas Sphere (1999)
Hanawa, Tomoyuki, Matsumoto, Tomoaki
We discuss stability of dynamically collapsing gas spheres. We use a similarity solution for a dynamically collapsing sphere as the unperturbed state. In the similarity solution the gas pressure is...
Jets from Time-Dependent Accretion Flows onto a Black Hole (1998)
Nobuta, Koji, Hanawa, Tomoyuki
We investigate time-dependent inviscid hydrodynamical accretion flows onto a black hole using numerical simulations. We consider the accretion that consists of hot tenuous gas with low specific...
Kazuya Saigo And, Kazuya Saigo, Tomoyuki Hanawa
We present similarity solutions which describe the runaway collapse of a rotating isothermal cloud and its subsequent inside-out collapse. The similarity solutions contain the sound speed, c s , and...
We present similarity solutions which describe the runaway collapse of a rotating isothermal cloud and its subsequent inside-out collapse. The similarity solutions contain the sound speed, c s , and...
Usami, Masatoshi, Hanawa, Tomoyuki, Fujimoto, Mitsuaki
We study the gravitational instability of an isothermal gaseous slab formed by cloud-cloud collision and compression at the cloud interface. The compressed gaseous slab rotates and has velocity shear...
Fragmentation of a Magnetized Filamentary Molecular Cloud Rotating around its Axis (1994)
Matsumoto, Tomoaki, Nakamura, Fumitaka, Hanawa, Tomoyuki
The dynamical instability of a self-gravitating magnetized filamentary cloud was investigated while taking account of rotation around its axis. The filamentary cloud of our model is supported against...
Sequential Star Formation in Taurus Molecular Cloud 1 (1993)
Hanawa, Tomoyuki, Yamamoto, Satoshi, Hirahara, Yasuhiro
We discuss the fragmentation of a filamentary cloud on the basis of a 1-dimensional hydrodynamical simulation of a self-gravitating gas cloud. The simulation shows that dense cores are produced with...