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相关论文: Nonaxisymmetric Evolution of Magnetically Subcriti…

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We study the non-axisymmetric evolution of magnetized clouds, using a 2D MHD code based on the physically motivated thin-disk approximation. We found that such clouds become unstable to non-axisymmetric perturbations after the supercritical…

天体物理学 · 物理学 2009-11-07 Fumitaka Nakamura , Zhi-Yun Li

In the standard scenario of isolated low-mass star formation, strongly magnetized molecular clouds are envisioned to condense gradually into cores, driven by ambipolar diffusion. Once the cores become magnetically supercritical, they…

天体物理学 · 物理学 2007-05-23 Fumitaka Nakamura , Zhi-Yun Li

Isolated low-mass stars are formed in dense cores of molecular clouds. In the standard picture, the cores are envisioned to condense out of strongly magnetized clouds through ambipolar diffusion. Most previous calculations based on this…

天体物理学 · 物理学 2009-11-07 Zhi-Yun Li , Fumitaka Nakamura

This is the first paper about the fragmentation and mass outflow in the molecular cloud by using three-dimensional MHD nested-grid simulations. The binary star formation process is studied paying particular attention to the fragmentation of…

天体物理学 · 物理学 2009-11-10 Masahiro N Machida , Kohji Tomisaka , Tomoaki Matsumoto

We study numerically the ambipolar diffusion-driven evolution of non-rotating, magnetically subcritical, disk-like molecular clouds, assuming axisymmetry. Previous similar studies have concentrated on the formation of single magnetically…

天体物理学 · 物理学 2009-11-06 Zhi-Yun Li

We extend our earlier work on ambipolar diffusion induced formation of protostellar cores in isothermal sheet-like magnetic interstellar clouds, by studying nonaxisymmetric collapse for the physically interesting regime of magnetically…

天体物理学 · 物理学 2009-11-10 Shantanu Basu , Glenn E. Ciolek

We formulate the problem of the formation and collapse of nonaxisymmetric protostellar cores in weakly ionized, self-gravitating, magnetic molecular clouds. In our formulation, molecular clouds are approximated as isothermal, thin (but with…

天体物理学 · 物理学 2011-02-11 Glenn E. Ciolek , Shantanu Basu

We demonstrate that the formation of collapsing cores in subcritical clouds is accelerated by nonlinear flows, by performing three-dimensional non-ideal MHD simulations. An initial random supersonic (and trans-Alfvenic) turbulent-like flow…

天体物理学 · 物理学 2009-11-13 Takahiro Kudoh , Shantanu Basu

We present an idealized, spherical model of the evolution of a magnetized molecular cloud due to ambipolar diffusion. This model allows us to follow the quasi-static evolution of the cloud's core prior to collapse and the subsequent…

天体物理学 · 物理学 2009-10-30 P. N. Safier , C. F. McKee , S. W. Stahler

We use magnetohydrodynamical simulations of converging flows to investigate the process of molecular cloud formation and evolution out of the magnetised ISM. Here, we investigate whether the observed subcritical HI clouds can become…

星系天体物理 · 物理学 2015-06-02 Bastian Körtgen , Robi Banerjee

We employ the three-dimensional magnetohydrodynamic simulation including ambipolar diffusion to study the gravitationally-driven fragmentation of subcritical molecular clouds, in which the gravitational fragmentation is stabilized as long…

太阳与恒星天体物理 · 物理学 2015-05-20 Takahiro Kudoh , Shantanu Basu

Molecular-line observations of star-forming cloud cores indicate that they are not the flattened structures traditionally considered by theory. Rather, they are elongated, perhaps in the direction of their internal magnetic field. We are…

天体物理学 · 物理学 2009-11-06 Charles L. Curry , Steven W. Stahler

Fragmentation and binary formation processes are studied using three-dimensional resistive MHD nested grid simulations. Starting with a Bonnor-Ebert isothermal cloud rotating in a uniform magnetic field, we calculate the cloud evolution…

天体物理学 · 物理学 2009-11-13 Masahiro N. Machida , Kohji Tomisaka , Tomoaki Matsumoto , Shu-ichiro Inutsuka

We discuss the lifetimes and evolution of clumps and cores formed as turbulent density fluctuations in nearly isothermal molecular clouds. In the non-magnetic case, clumps are unlikely to reach a hydrostatic state, and instead are expected…

We present results from an extensive set of simulations of gravitational fragmentation in the presence of magnetic fields and ambipolar diffusion. The average fragmentation spacing in the nonlinear phase of evolution is in excellent…

天体物理学 · 物理学 2008-12-18 Shantanu Basu , Glenn E. Ciolek , James Wurster

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 adiabatic gas forms a protostellar first…

天体物理学 · 物理学 2009-11-13 Masahiro N Machida , Tomoaki Matsumoto , Tomoyuki Hanawa , Kohji Tomisaka

We formulate the problem of the formation and subsequent evolution of fragments (or cores) in magnetically-supported, self-gravitating molecular clouds in two spatial dimensions. The six-fluid (neutrals, electrons, molecular and atomic…

天体物理学 · 物理学 2011-02-11 Matthew W. Kunz , Telemachos Ch. Mouschovias

We investigate the formation and evolution of giant molecular clouds (GMCs) by the collision of convergent warm neutral medium (WNM) streams in the interstellar medium, in the presence of magnetic fields and ambipolar diffusion (AD),…

Evolution of stellar bars in disk galaxies is accompanied by dynamical instabilities and secular changes. Following the vertical buckling instability, the bars are known to weaken dramatically and develop a pronounced boxy/peanut shape when…

天体物理学 · 物理学 2009-11-13 Inma Martinez-Valpuesta , Isaac Shlosman , Clayton Heller

In a previous paper we formulated the problem of the formation and evolution of fragments (or cores) in magnetically-supported, self-gravitating molecular clouds in axisymmetric geometry, accounting for the effects of ambipolar diffusion…

太阳与恒星天体物理 · 物理学 2015-05-18 M. W. Kunz , T. Ch. Mouschovias
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