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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

In this work we extend the non-ideal magnetohydrodynamics (MHD) solver in the moving mesh code AREPO to include the Hall effect. The core of our algorithm is based on an estimation of the magnetic field gradients by a least-square…

Instrumentation and Methods for Astrophysics · Physics 2023-09-29 Oliver Zier , Alexander C. Mayer , Volker Springel

Protostellar disks around young protostars exhibit diverse properties, with their radii ranging from less than ten to several hundred au. To investigate the mechanisms shaping this disk radius distribution, we compiled a sample of 27 Class…

Solar and Stellar Astrophysics · Physics 2024-08-23 Hsi-Wei Yen , Yueh-Ning Lee

The gas temperature in protoplanetary disks (PPDs) is determined by a combination of irradiation heating and accretion heating, with the latter conventionally attributed to turbulent dissipation. However, recent studies have suggested that…

Earth and Planetary Astrophysics · Physics 2019-03-01 Shoji Mori , Xue-Ning Bai , Satoshi Okuzumi

We present results from radiation non-ideal magnetohydrodynamics (MHD) calculations that follow the collapse of rotating, magnetised, molecular cloud cores to stellar densities. These are the first such calculations to include all three…

Solar and Stellar Astrophysics · Physics 2018-02-07 James Wurster , Matthew R. Bate , Daniel J. Price

In certain astrophysical systems the commonly employed ideal magnetohydrodynamics (MHD) approximation breaks down. Here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code AREPO. We…

Instrumentation and Methods for Astrophysics · Physics 2018-03-09 Federico Marinacci , Mark Vogelsberger , Rahul Kannan , Philip Mocz , Rüdiger Pakmor , Volker Springel

We study the evolution of the protoplanetary discs (PPDs) in the presence of magnetically driven winds with the stress relations motivated by the non-ideal MHD disc simulations. Contribution of the magnetic winds in the angular momentum…

Astrophysics of Galaxies · Physics 2019-07-31 Mohsen Shadmehri , Sayyedeh Masoumeh Ghoreyshi

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

In this paper, we provide a more accurate description of the evolution of the magnetic flux redistribution during prestellar core collapse by including resistive terms in the magnetohydrodynamics (MHD) equations. We focus more particularly…

Solar and Stellar Astrophysics · Physics 2016-02-17 Jacques Masson , Gilles Chabrier , Patrick Hennebelle , Neil Vaytet , Benoit Commerçon

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

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

The effect of the Hall term on the evolution of the magnetorotational instability (MRI) in weakly ionized accretion disks is investigated using local axisymmetric simulations. First, we show that the Hall term has important effects on the…

Astrophysics · Physics 2009-11-07 Takayoshi Sano , James M. Stone

Recent observations revealed organised structures in protoplanetary disks, such as axisymmetric rings or horseshoe concen- trations evocative of large-scale vortices. These structures are often interpreted as the result of planet-disc…

Earth and Planetary Astrophysics · Physics 2016-04-20 William Béthune , Geoffroy Lesur , Jonathan Ferreira

The effect of misalignment between the magnetic field $\magB$ and the angular momentum $\Jang$ of molecular cloud cores on the angular momentum evolution during the gravitational collapse is investigated by ideal and non-ideal MHD…

Solar and Stellar Astrophysics · Physics 2018-11-28 Y. Tsukamoto , S. Okuzumi , K. Iwasaki , M. N. Machida , S. Inutsuka

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

We study particle trapping at the edge of a gap opened by a planet in a protoplanetary disk. In particular, we explore the effects of turbulence driven by the magnetorotational instability on particle trapping, using global…

Solar and Stellar Astrophysics · Physics 2015-06-19 Zhaohuan Zhu , James M. Stone

Cool weakly ionized gaseous rotating disk, are considered by many models as the origin of the evolution of protoplanetary clouds. Instabilities against perturbations in such disks play an important role in the theory of the formation of…

Astrophysics · Physics 2011-02-11 E. Liverts , M. Mond , A. D. Chernin

We investigate the possibility of the growth of magnetorotational instability (MRI) in disks around Class 0 protostars. We construct a disk model and calculate the chemical reactions of neutral and charged atoms, molecules and dust grains…

Solar and Stellar Astrophysics · Physics 2021-05-12 Yoshihiro Kawasaki , Shunta Koga , Masahiro N. Machida

The regions of protoplanetary discs where planets can form are believed to be weakly ionised, suggesting thereby that non-ideal magneto-hydrodynamics (MHD) effects play an important role in the disc dynamics and in the planet formation…

Earth and Planetary Astrophysics · Physics 2026-04-14 Arnaud Pierens , Min-Kai Lin

Interstellar magnetic fields influence all stages of the process of star formation, from the collapse of molecular cloud cores to the formation of protostellar jets. This requires us to have a full understanding of the physical properties…

Astrophysics · Physics 2009-11-13 Cecilia Pinto , Daniele Galli , Francesca Bacciotti
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