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Protoplanetary disks are likely to be threaded by a weak net flux of vertical magnetic field that is a remnant of the much larger fluxes present in molecular cloud cores. If this flux is approximately conserved its dynamical importance will…

Earth and Planetary Astrophysics · Physics 2015-06-17 Philip J. Armitage , Jacob B. Simon , Rebecca G. Martin

Magnetic fields play a vital role in numerous astrophysical processes such as star formation and the interstellar medium. In particular, their role in the formation and evolution of galaxies is not well understood. This paper presents…

Astrophysics of Galaxies · Physics 2021-12-10 Huai-Hsuan Chiu , Ke-Jung Chen

The protostellar jets driven by the formation of the first stars are studied by using MHD nested grid simulations. Starting from a slowly rotating spherical cloud of 5.1 times 10^4 Msun permeated by a uniform magnetic field, we follow the…

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

Star formation proceeds via the collapse of a molecular cloud core over multiple dynamical timescales. Turbulence within cores results in a spatially non-uniform angular momentum of the cloud, causing a stochastic variation in orientation…

Earth and Planetary Astrophysics · Physics 2015-06-23 Christopher Spalding , Konstantin Batygin , Fred C. Adams

Improving our understanding of the earliest stages of star formation is crucial to gain insight into the origin of stellar masses, multiple systems, and protoplanetary disks. We discuss recent advances made in this area thanks to detailed…

Astrophysics · Physics 2007-05-23 Philippe Andre , Arnaud Belloche , Patrick Hennebelle , Derek Ward-Thompson

Star formation is thought to be triggered by the gravitational collapse of the dense cores of molecular clouds. Angular momentum conservation during the collapse results in the progressive increase of the centrifugal force, which eventually…

Earth and Planetary Astrophysics · Physics 2009-03-11 Raquel Salmeron

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

We investigate the evolution of a disk wind into a collimated jet under the influence of magnetic diffusivity. Using the ZEUS-3D code in the axisymmetry option we solve the time-dependent resistive MHD equations for a model setup of a…

Astrophysics · Physics 2007-05-23 M. Cemeljic , Ch. Fendt

Theoretically, misalignment between the magnetic field and rotational axis in a dense core is considered to be dynamically important in the star formation process, however, extent of this influence remains observationally unclear. For a…

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

The role of magnetic fields in the early stages of star formation is not well constrained. In order to discriminate between different star formation models, we analyze 3D magnetohydrodynamic simulations of low-mass cores and explore the…

Astrophysics of Galaxies · Physics 2017-01-18 Joyce W. Y. Lee , Charles L. H. Hull , Stella S. R. Offner

We present an implementation of radiative transfer with flux-limited diffusion (FLD) for the moving-mesh code {\small AREPO} and use the method in a physical model for the formation of protostars with non-ideal…

Solar and Stellar Astrophysics · Physics 2025-12-23 Alexander C. Mayer , Rüdiger Pakmor , Thorsten Naab , Oliver Zier , Alexei V. Ivlev , Tommaso Grassi , Paola Caselli , Volker Springel

We investigate the role of ambipolar diffusion (AD) in collisions between magnetized giant molecular clouds (GMCs), which may be an important mechanism for triggering star cluster formation. Three dimensional simulations of GMC collisions…

Astrophysics of Galaxies · Physics 2017-10-18 Duncan Christie , Benjamin Wu , Jonathan C. Tan

We explore the pulsationally driven orbital mass ejection mechanism for Be star disc formation using isothermal, 3D magnetohydrodynamic (MHD) and hydrodynamic simulations. Non-radial pulsations are added to a star rotating at 95\% of…

Solar and Stellar Astrophysics · Physics 2021-11-09 Sean M. Ressler

Beginning with cosmological initial conditions at z=100, we simulate the effects of magnetic fields on the formation of Population III stars and compare our results with the predictions of Paper I. We use Gadget-2 to follow the evolution of…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-04 Athena Stacy , Christopher F. McKee , Aaron T. Lee , Richard I. Klein , Pak Shing Li

We numerically model evolution of magnetic fields inside a neutron star under the influence of ambipolar diffusion in the weak-coupling mode in the one-fluid MHD approximation. Our simulations are three-dimensional and performed in…

High Energy Astrophysical Phenomena · Physics 2022-11-09 Andrei P. Igoshev , Rainer Hollerbach

We discuss the factors influencing the formation and gravitational fragmentation of protostellar discs. We start with a review of how observations of prestellar cores can be analysed statistically to yield plausible initial conditions for…

Solar and Stellar Astrophysics · Physics 2016-05-19 A. P. Whitworth , O. D. Lomax

We present the highest-resolution three-dimensional simulation to date of the collapse of an atomic cooling halo in the early Universe. We use the moving-mesh code arepo with the primordial chemistry module introduced in Greif (2014), which…

Astrophysics of Galaxies · Physics 2014-12-08 Fernando Becerra , Thomas H. Greif , Volker Springel , Lars Hernquist

Stellar feedback in the form of radiation pressure and magnetically-driven collimated outflows may limit the maximum mass that a star can achieve and affect the star-formation efficiency of massive pre-stellar cores. Here we present a…

Solar and Stellar Astrophysics · Physics 2020-07-29 Anna L. Rosen , Mark R. Krumholz