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Related papers: The impact of the Hall effect during cloud core co…

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We have performed magnetohydrodynamic (MHD) simulations of the collapse and fragmentation of molecular cloud cores using a new algorithm for MHD within the smoothed particle hydrodynamics (SPH) method, that enforces the zero magnetic…

Astrophysics · Physics 2008-11-26 Daniel J. Price , Matthew R. Bate

The evolution of the magnetic field and angular momentum in the collapsing cloud core is studied using three-dimensional resistive MHD nested grid simulations. Starting with a Bonnor-Ebert isothermal cloud rotating in a uniform magnetic…

Astrophysics · Physics 2009-11-13 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

Stars and more particularly massive stars, have a drastic impact on galaxy evolution. Yet the conditions in which they form and collapse are still not fully understood. In particular, the influence of the magnetic field on the collapse of…

Astrophysics of Galaxies · Physics 2015-05-27 P. Hennebelle , B. Commercon , M. Joos , R. S. Klessen , M. Krumholz , J. C. Tan , R. Teyssier

We present new simulations of the evolution of axially symmetric magnetic fields in neutron star crusts under the influence of the Hall effect and subdominant Ohmic dissipation. In the Hall effect, differential rotation of the electron…

Solar and Stellar Astrophysics · Physics 2015-06-18 K. N. Gourgouliatos , A. Cumming

The magnetic fields affect collapse of molecular cloud cores. Here, we consider a collapsing core with an axial magnetic field and investigate its effect on infall of matter and formation of accretion disk. For this purpose, the equations…

Astrophysics of Galaxies · Physics 2015-05-27 Mohsen Nejad-Asghar

We use magnetic collapse models to place some constraints on the formation and angular momentum evolution of circumstellar disks which are embedded in magnetized cloud cores. Previous models have shown that the early evolution of a…

Astrophysics · Physics 2009-10-30 Shantanu Basu

We study numerically the collapse of rotating, magnetized molecular cloud cores, focusing on rotation and magnetic braking during the main accretion phase of isolated star formation. Motivated by previous numerical work and analytic…

Astrophysics · Physics 2009-11-10 A. Allen , Z. Y. Li , F. H. Shu

The grand question of star and planet formation is the distribution of magnetic flux in the protoplanetary disks. To answer it, a detailed self-consistent chemical evolution is needed to describe the magnetic dissipation in the collapsing…

Solar and Stellar Astrophysics · Physics 2017-07-26 Natalia Dzyurkevich , Benoit Commercon , Pierre Lesaffre , Dimitry Semenov

In the present-day universe, magnetic fields play such essential roles in star formation as angular momentum transport and outflow driving, which control circumstellar disc formation/fragmentation and also the star formation efficiency.…

Astrophysics of Galaxies · Physics 2022-12-28 Kenji Eric Sadanari , Kazuyuki Omukai , Kazuyuki Sugimura , Tomoaki Matsumoto , Kengo Tomida

We investigate the effect of non-ideal magnetohydrodynamics (MHD) on the formation of binary stars using a suite of three-dimensional smoothed particle magnetohydrodynamics simulations of the gravitational collapse of one solar mass,…

Solar and Stellar Astrophysics · Physics 2016-12-08 James Wurster , Daniel J. Price , Matthew R. Bate

Non-ideal MHD effects have been shown recently as a robust mechanism of averting the magnetic braking "catastrophe" and promoting protostellar disc formation. However, the magnetic diffusivities that determine the efficiency of non-ideal…

Solar and Stellar Astrophysics · Physics 2021-05-12 Bo Zhao , Paola Caselli , Zhi-Yun Li , Ruben Krasnopolsky , Hsien Shang , Ka Ho Lam

We present self-similar solutions that describe the gravitational collapse of rotating, isothermal, magnetic molecular-cloud cores, relevant to the formation of rotationally supported protostellar disks. This work focuses on the evolution…

Astrophysics · Physics 2009-11-07 Ruben Krasnopolsky , Arieh Konigl

Using resistive magnetohydrodynamics simulation, we investigate circumstellar disk formation in a strongly magnetized cloud. As the initial state, an isolated cloud core embedded in a low-density interstellar medium with a uniform magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-19 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

Non-ideal magnetohydrodynamic (MHD) processes -- namely Ohmic resistivity, ambipolar diffusion and the Hall effect -- modify the early stages of the star formation process and the surrounding environment. Collectively, they have been shown…

Astrophysics of Galaxies · Physics 2021-08-18 James Wurster , Matthew R. Bate , Ian A. Bonnell

The angular momentum of galactic discs in semi-analytic models of galaxy formation is usually updated in time as material is accreted to the disc by adopting a constant dimensionless spin parameter and little attention is paid to the…

Astrophysics of Galaxies · Physics 2015-06-17 Nelson Padilla , Salvador Salazar-Albornoz , Sergio Contreras , Sofia Cora , Andres Ruiz

We perform 3D stratified shearing-box MHD simulations on the gas dynamics of protoplanetary disks threaded by net vertical magnetic field Bz. All three non-ideal MHD effects, Ohmic resistivity, the Hall effect and ambipolar diffusion are…

Earth and Planetary Astrophysics · Physics 2015-06-22 Xue-Ning Bai

Neutron star magnetic field evolution is mediated through the Hall effect and Ohmic dissipation in the crust while ambipolar diffusion is taking place in the core. These effects have been studied in detail in either part of the star,…

High Energy Astrophysical Phenomena · Physics 2024-02-28 Dimitrios Skiathas , Konstantinos N. Gourgouliatos

The breakdown of flux-freezing in molecular clouds and protostellar discs is usually approximated by ambipolar diffusion at low densities or by resistive diffusion at high densities. Here I discuss an intermediate regime in which the Hall…

Astrophysics · Physics 2009-11-10 Mark Wardle

If the angular momentum of the molecular cloud core were conserved during the star formation process, a new-born star would rotate much faster than its fission speed. This constitutes the angular momentum problem of new-born stars. In this…

Astrophysics · Physics 2009-10-31 Kohji Tomisaka

Collapse of the rotating magnetized molecular cloud core is studied with the axisymmetric magnetohydrodynamical (MHD) simulations. Due to the change of the equation of state of the interstellar gas, the molecular cloud cores experience…

Astrophysics · Physics 2009-11-06 Kohji Tomisaka