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Related papers: Magnetic Braking and Protostellar Disk Formation: …

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Protostars are born in magnetized environments. As a consequence, the formation of protostellar disks can be suppressed by the magnetic field efficiently removing angular momentum of the infalling material. Non-ideal MHD effects are…

Solar and Stellar Astrophysics · Physics 2024-04-26 Travis J. Thieme , Shih-Ping Lai , Yueh-Ning Lee , Sheng-Jun Lin , Hsi-Wei Yen

We follow the ambipolar-diffusion--driven formation and evolution of a fragment in a magnetically supported molecular cloud, until a hydrostatic protostellar core forms at its center. This problem was formulated in Paper I. We determine the…

Astrophysics · Physics 2011-02-11 Konstantinos Tassis , Telemachos Ch. Mouschovias

We study mass accretion and ejection in the vicinity of massive star forming cores using high-resolution (5 au) 3D AMR numerical simulations. We investigate the mechanisms at the origin of outflows and characterise the properties of the…

Solar and Stellar Astrophysics · Physics 2022-02-02 Benoît Commerçon , Matthias González , Raphaël Mignon-Risse , Patrick Hennebelle , Neil Vaytet

Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the…

Solar and Stellar Astrophysics · Physics 2011-10-12 Catherine Braiding

The problem of the late accretion phase of the evolution of an axisymmetric, isothermal magnetic disk surrounding a forming star has been formulated in a companion paper. The "central sink approximation" is used to circumvent the problem of…

Astrophysics · Physics 2009-11-10 Konstantinos Tassis , Telemachos Ch. Mouschovias

It has been shown that a realistic level of magnetization of dense molecular cloud cores can suppress the formation of a rotationally supported disk (RSD) through catastrophic magnetic braking in the axisymmetric ideal MHD limit. In this…

Solar and Stellar Astrophysics · Physics 2016-06-15 Bo Zhao , Paola Caselli , Zhi-Yun Li , Ruben Krasnopolsky , Hsien Shang , Fumitaka Nakamura

In star formation, magnetic fields act as a cosmic angular momentum extractor that increases mass accretion rates onto protostars and in the process, creates spectacular outflows. However, recently it has been argued that this magnetic…

Solar and Stellar Astrophysics · Physics 2014-11-20 Dennis F. Duffin , Ralph E. Pudritz

We consider formation of accretion disks from a realistically turbulent molecular gas using 3D MHD simulations. In particular, we analyze the effect of the fast turbulent reconnection described by the Lazarian & Vishniac (1999) model for…

Solar and Stellar Astrophysics · Physics 2016-03-16 Diego F. González-Casanova , Reinaldo Santos-Lima , Alexander Lazarian

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

We present results from the first radiation non-ideal magnetohydrodynamics (MHD) simulations of low-mass star cluster formation that resolve the fragmentation process down to the opacity limit. We model 50~M$_\odot$ turbulent clouds…

Solar and Stellar Astrophysics · Physics 2019-08-12 James Wurster , Matthew R. Bate , Daniel J. Price

Non-ideal magnetohydrodynamics (MHD) is the dominant process. We investigate the effect of magnetic fields (ideal and non-ideal) and turbulence (sub- and transsonic) on the formation of circumstellar discs that form nearly simultaneously…

Solar and Stellar Astrophysics · Physics 2020-06-03 James Wurster , Benjamin T. Lewis

This paper considers gravitational perturbations in geometrically thin disks with rotation curves dominated by a central object, but with substantial contributions from magnetic pressure and tension. The treatment is general, but the…

Astrophysics of Galaxies · Physics 2015-05-20 Susana Lizano , Daniele Galli , Mike J. Cai , Fred C. Adams

Recent observations have suggested that circumstellar disks may commonly form around young stellar objects. Although the formation of circumstellar disks can be a natural result of the conservation of angular momentum in the parent cloud,…

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

We consider rotating magnetic stars with winds and disks. We establish a theorem that relates the angular velocity of a disk region with no meridional motion to the angular velocity of the star. Also, we show that for a given value of the…

Astrophysics · Physics 2009-11-07 M. Maheswaran

Magnetic fields play an important role in star formation by regulating the removal of angular momentum from collapsing molecular cloud cores. Hall diffusion is known to be important to the magnetic field behaviour at many of the…

Solar and Stellar Astrophysics · Physics 2015-05-30 Catherine R. Braiding , Mark Wardle

Misalignment between rotation and magnetic field has been suggested to be one type of physical mechanisms which can easen the effects of magnetic braking during collapse of cloud cores leading to formation of protostellar disks. However,…

Solar and Stellar Astrophysics · Physics 2022-04-06 Weixiao Wang , Miikka S. Väisälä , Hsien Shang , Ruben Krasnopolsky , Zhi-Yun Li , Ka Ho Lam , Feng Yuan

We present simulations of the supernova-driven turbulent interstellar medium (ISM) in a simulation domain of volume $(256\,{\rm pc})^3$ within which we resolve the formation of protostellar accretion disks and their stellar cores to spatial…

We investigate the roles of magnetic fields and ambipolar diffusion during prestellar core formation in turbulent giant molecular clouds (GMCs), using three-dimensional numerical simulations. Our simulations focus on the shocked layer…

Solar and Stellar Astrophysics · Physics 2015-06-19 Che-Yu Chen , Eve C. Ostriker

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