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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

Magnetic fields are usually considered dynamically important in star formation when the dimensionless mass-to-flux ratio is close to, or less than, unity (lambda<~1). We show that, in disk formation, the requirement is far less stringent.…

Astrophysics · Physics 2009-11-13 Richard R. Mellon , Zhi-Yun Li

The formation of protostellar disks out of molecular cloud cores is still not fully understood. Under ideal MHD conditions, the removal of angular momentum from the disk progenitor by the typically embedded magnetic field may prevent the…

Astrophysics of Galaxies · Physics 2015-05-30 R. Santos-Lima , E. M. de Gouveia Dal Pino , A. Lazarian

The gas from which stars form is magnetized, and strong magnetic fields can efficiently transport angular momentum. Most theoretical models of this phenomenon find that it should prevent formation of large (>100 AU), rotationally-supported…

Solar and Stellar Astrophysics · Physics 2015-06-12 Mark R. Krumholz , Richard M. Crutcher , Charles L. H. Hull

Truncated abstract: The formation of a protostellar disc is a natural outcome during the star formation process. As gas in a molecular cloud core collapses under self-gravity, the angular momentum of the gas will slow its collapse on small…

Solar and Stellar Astrophysics · Physics 2018-12-18 James Wurster , Zhi-Yun Li

Stars form in dense cores of molecular clouds that are observed to be significantly magnetized. In the simplest case of a laminar (non-turbulent) core with the magnetic field aligned with the rotation axis, both analytic considerations and…

Solar and Stellar Astrophysics · Physics 2015-06-12 Zhi-Yun Li , Ruben Krasnopolsky , Hsien Shang

In the context of star and planet formation, understanding the formation of disks is of fundamental importance. Previous studies found that the magnetic field has a very strong impact on the collapse of a prestellar cloud, particularly in…

Astrophysics of Galaxies · Physics 2015-05-14 P. Hennebelle , A. Ciardi

The formation of circumstellar discs is a critical step in the formation of stars and planets. Magnetic fields can strongly affect the evolution of angular momentum during prestellar core collapse, potentially leading to the failure of…

Astrophysics of Galaxies · Physics 2024-03-18 Chong-Chong He , Massimo Ricotti

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 pre-stellar cores in which low mass stars form are generally well magnetized. Our simulations show that early protostellar discs are massive and experience strong magnetic torques in the form of magnetic braking and protostellar…

Solar and Stellar Astrophysics · Physics 2015-05-20 Dennis Duffin , Ralph E. Pudritz

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

The transport of angular momentum is capital during the formation of low-mass stars; too little removal and rotation ensures stellar densities are never reached, too much and the absence of rotation means no protoplanetary disks can form.…

Solar and Stellar Astrophysics · Physics 2018-07-04 Neil Vaytet , Benoît Commerçon , Jacques Masson , Matthias González , Gilles Chabrier

Through the magnetic braking and the launching of protostellar outflows, magnetic fields play a major role in the regulation of angular momentum in star formation, which directly impacts the formation and evolution of protoplanetary disks…

Solar and Stellar Astrophysics · Physics 2020-09-04 Pierre Marchand , Kengo Tomida , Kei Tanaka , Benoît Commerçon , Gilles Chabrier

While it is generally accepted that the magnetic field and its non-ideal effects play important roles during the stellar formation, simple models of pure hydrodynamics and angular momentum conservation are still widely employed in the…

Earth and Planetary Astrophysics · Physics 2021-04-21 Yueh-Ning Lee , Sébastien Charnoz , Patrick Hennebelle

The magnetic field plays a central role in the formation and evolution of circumstellar disks. The magnetic field connects the rapidly rotating central region with the outer envelope and extracts angular momentum from the central region…

Solar and Stellar Astrophysics · Physics 2016-03-24 Yusuke Tsukamoto

Stars form from the gravitational collapse of turbulent, magnetized molecular cloud cores. Our non-ideal MHD simulations reveal that the intrinsically anisotropic magnetic resistance to gravity during the core collapse naturally generates…

Earth and Planetary Astrophysics · Physics 2025-07-11 Yisheng Tu , Zhi-Yun Li , Ka Ho Lam , Kengo Tomida , Chun-Yen Hsu

Protoplanetary disks form through angular momentum conservation in collapsing dense cores. In this work, we perform the first simulations with a maximal resolution down to the astronomical unit (au) of protoplanetary disk formation, through…

Although protostars and disks are often studied separately owing to numerical and observational challenges, breakthroughs in recent years have highlighted the need to study both objects in concert. The role of magnetic fields in this regard…

Solar and Stellar Astrophysics · Physics 2025-04-30 Adnan Ali Ahmad , Matthias González , Patrick Hennebelle , Ugo Lebreuilly , Benoît Commerçon

Isolated low-mass stars are formed, in the standard picture, from the collapse of dense cores condensed out of strongly magnetized molecular clouds. The dynamically collapsing inflow traps nearly half of the critical magnetic flux needed…

Astrophysics · Physics 2009-11-07 Zhi-Yun Li

Are magnetic fields important in primordial star formation? Assuming that star formation occurs via an accretion disk that is turbulent, initially because of local gravitational instability, we calculate the disk structure for realistic…

Astrophysics · Physics 2009-11-10 Jonathan C. Tan , Eric G. Blackman
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