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Related papers: On the Grain-Modified Magnetic Diffusivities in Pr…

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We analyze the ionization state of the magnetohydrodynamically turbulent protoplanetary disks and propose a new mechanism of sustaining ionization. First, we show that in the quasi-steady state of turbulence driven by magnetorotational…

Astrophysics · Physics 2009-11-11 Shu-ichiro Inutsuka , Takayoshi Sano

Magnetic fields have been shown both observationally and through theoretical work to be an important factor in the formation of protostars and their accretion disks. Accurate modelling of the evolution of the magnetic field in…

Observations of protoplanetary disks (PPDs) at sub-mm wavelengths suggest that polarisation is caused by scattering of thermal radiation. Most of the dust models that are used to explain these observations have major drawbacks: They either…

Solar and Stellar Astrophysics · Physics 2021-04-21 Robert Brunngräber , Sebastian Wolf

Giant planets embedded in protoplanetary disks (PPDs) can create annulus density gaps around their orbits in the type-II regime, potentially responsible for the ubiquity of annular substructures observed in PPDs. Despite of substantial…

Earth and Planetary Astrophysics · Physics 2024-07-23 Yuhiko Aoyama , Xuening Bai

We review the current status of studies on accretion and protoplanetary disks of young stars with large-scale magnetic fields. Observational data on magnetic fields of the disks are compiled and analysed. Modern analytical and numerical MHD…

Solar and Stellar Astrophysics · Physics 2024-01-26 Sergey A. Khaibrakhmanov

Efficient magnetic braking is a formidable obstacle to the formation of rotationally supported disks (RSDs) around protostars in magnetized dense cores. We have previously shown, through 2D (axisymmetric) non-ideal MHD simulations, that…

Solar and Stellar Astrophysics · Physics 2017-11-17 Bo Zhao , Paola Caselli , Zhi-Yun Li , Ruben Krasnopolsky

Dust grains influence many aspects of star formation, including planet formation, opacities for radiative transfer, chemistry, and the magnetic field via Ohmic, Hall, and ambipolar diffusion. The size distribution of the dust grains is the…

Solar and Stellar Astrophysics · Physics 2023-02-08 Pierre Marchand , Ugo Lebreuilly , Mordecai-Mark Mac Low , Vincent Guillet

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

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

We discovered a new growth mode of dust grains to km-sized bodies in protoplanetary disks that evolve by viscous accretion and magnetically driven disk winds (MDWs). We solved an approximate coagulation equation of dust grains with…

Earth and Planetary Astrophysics · Physics 2021-03-17 Tetsuo Taki , Koh Kuwabara , Hiroshi Kobayashi , Takeru K. Suzuki

We propose a new evolutionary process of protoplanetary disks "co-evolution of dust grains and protoplanetary disks", revealed by dust-gas two-fluid non-ideal magnetohydrodynamics simulations considering the growth of dust and associated…

Solar and Stellar Astrophysics · Physics 2023-07-26 Yusuke Tsukamoto , Masahiro N. Machida , Shu-ichiro Inutsuka

The origin of polarized emission from protoplanetary disks is uncertain. Three mechanisms have been proposed for such polarized emission: grain alignment with magnetic fields, grain alignment with radiation gradients, and self-scattering of…

We present arcsecond-resolution Submillimeter Array (SMA) polarimetric observations of the 880 um continuum emission from the protoplanetary disks around two nearby stars, HD 163296 and TW Hydrae. Although previous observations and…

Solar and Stellar Astrophysics · Physics 2014-11-20 A. Meredith Hughes , David J. Wilner , Jungyeon Cho , Daniel P. Marrone , Alexandre Lazarian , Sean M. Andrews , Ramprasad Rao

Magnetic fields ($\textbf{B}$) are an important factor that controls the star formation process. The leading method to observe $\textbf{B}$ is using polarized thermal emission from dust grains aligned with $\textbf{B}$. However, in dense…

Astrophysics of Galaxies · Physics 2023-06-16 Nguyen Chau Giang , Thiem Hoang , Jeong-Gyu Kim , Le Ngoc Tram

We calculate the ionisation fraction in protostellar disk models using two different gas-phase chemical networks, and examine the effect of turbulent mixing by modelling the diffusion of chemical species vertically through the disk. The aim…

Astrophysics · Physics 2009-11-11 Martin Ilgner , Richard P. Nelson

The presence of dust grains profoundly affects the diffusion of the magnetic field in molecular clouds. When the electrons and ions are well coupled to the magnetic field and charged grains are only indirectly coupled, emergent Hall…

Astrophysics of Galaxies · Physics 2019-02-13 B. P. Pandey , S. V. Vladimirov

We investigate the dynamics of dust concentration in actively accreting, substructured, non-ideal MHD wind-launching disks using 2D and 3D simulations incorporating pressureless dust fluids of various grain sizes and their aerodynamic…

Earth and Planetary Astrophysics · Physics 2025-05-14 Chun-Yen Hsu , Zhi-Yun Li , Yisheng Tu , Xiao Hu , Min-Kai Lin

We use local numerical simulations to investigate the strength and nature of magnetohydrodynamic (MHD) turbulence in the outer regions of protoplanetary disks, where ambipolar diffusion is the dominant non-ideal MHD effect. The simulations…

Solar and Stellar Astrophysics · Physics 2015-06-11 Jacob B. Simon , Xue-Ning Bai , James M. Stone , Philip J. Armitage , Kris Beckwith

Magnetized winds may be important in dispersing protoplanetary disks and influencing planet formation. We carry out global full magnetohydrodynamic simulations in axisymmetry, coupled with ray-tracing radiative transfer, consistent…

Earth and Planetary Astrophysics · Physics 2019-04-03 Lile Wang , Xue-Ning Bai , Jeremy Goodman

Due to the gravitational influence of density fluctuations driven by magneto-rotational instability in the gas disk, planetesimals and protoplanets undergo diffusive radial migration as well as changes in other orbital properties. The…

Earth and Planetary Astrophysics · Physics 2015-05-27 Chao-Chin Yang , Mordecai-Mark Mac Low , Kristen Menou