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Related papers: On the torque exerted by a warped, magnetically th…

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We study a warping instability of a geometrically thin, non-self-gravitating disk surrounding binary supermassive black holes on a circular orbit. Such a circumbinary disk is subject to not only tidal torques due to the binary gravitational…

Astrophysics of Galaxies · Physics 2015-06-19 Kimitake Hayasaki , Bong Won Sohn , Atsuo T. Okazaki , Taehyun Jung , Guangyao Zhao , Tsuguya Naito

Gravitational-wave diagnostics are developed for discriminating between varieties of mixed poloidal-toroidal magnetic fields in neutron stars, with particular emphasis on differentially rotating protoneutron stars. It is shown that tilted…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Paul D. Lasky , Andrew Melatos

(Abridged) The rotational evolution of isolated neutron stars is dominated by the magnetic field anchored to the solid crust of the star. Assuming that the core field evolves on much longer timescales, the crustal field evolves mainly…

Solar and Stellar Astrophysics · Physics 2013-06-11 Jose A. Pons , Daniele Vigano , Ulrich Geppert

Context. Changes of the rotational period observed in various magnetized accreting sources are generally attributed to the interaction between the in-falling plasma and the large-scale magnetic field of the accretor. A number of models have…

Despite extensive study, the mechanisms by which Be star disks acquire high densities and angular momentum while displaying variability on many time scales are still far from clear. In this paper, we discuss how magnetic torquing may help…

Astrophysics · Physics 2009-11-07 J. P. Cassinelli , J. C. Brown , M. Maheswaran , N. A. Miller , D. C. Telfer

We performed 2D and full 3D magnetohydrodynamic simulations of disk accretion to a rotating star with an aligned or misaligned dipole magnetic field. We investigated the rotational equilibrium state and derived from simulations the ratio…

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

A millisecond pulsar is a neutron star that has been substantially spun up by accretion from a binary companion. A previously unrecognized factor governing the spin evolution of such pulsars is the crucial effect of non-steady or transient…

High Energy Astrophysical Phenomena · Physics 2017-01-25 Sudip Bhattacharyya , Deepto Chakrabarty

Disks are essential to the formation of both stars and planets, but how they form in magnetized molecular cloud cores remains debated. This work focuses on how the disk formation is affected by turbulence and ambipolar diffusion (AD), both…

Solar and Stellar Astrophysics · Physics 2019-09-02 Ka Ho Lam , Zhi-Yun Li , Che-Yu Chen , Kengo Tomida , Bo Zhao

In this paper we review some aspects of the theory of magnetic threaded disks. We discuss in particular the equations that determine the position of the inner disk boundary by using different prescriptions for the neutron star-accretion…

Astrophysics · Physics 2009-11-13 E. Bozzo , L. Stella , M. Vietri , P. Ghosh

We use global magnetohydrodynamic simulations to study the influence of net vertical magnetic fields on the structure of geometrically thin ($H/r \approx 0.05$) accretion disks in the Newtonian limit. We consider initial mid-plane gas to…

High Energy Astrophysical Phenomena · Physics 2020-01-23 Bhupendra Mishra , Mitchell C. Begelman , Philip J. Armitage , Jacob B. Simon

We summarize recent 2D MHD simulations of line-driven stellar winds from rotating hot-stars with a dipole magnetic field aligned to the star's rotation axis. For moderate to strong fields, much wind outflow is initially along closed…

Astrophysics · Physics 2007-05-23 Stan Owocki , Asif ud-Doula

Young protostars embedded in circumstellar discs accrete from an angular momentum-rich mass reservoir. Without some braking mechanism, all stars should be spinning at or near break-up velocity. In this paper, we perform simulations of the…

Solar and Stellar Astrophysics · Physics 2015-05-28 Min-Kai Lin , Mark R. Krumholz , Kaitlin M. Kratter

Most analytic work to date on protostellar disks has focused on those in isolation from their environments. However, observations are now beginning to probe the earliest, most embedded phases of star formation, during which disks are…

Astrophysics · Physics 2009-11-13 Kaitlin M. Kratter , Christopher D. Matzner , Mark R. Krumholz , .

We investigate the dynamics of the accretion disks of young stars with fossil large-scale magnetic field. The author's magnetohydrodynamic (MHD) model of the accretion disks is generalized to consider the dynamical influence of the magnetic…

Solar and Stellar Astrophysics · Physics 2022-12-28 Sergey A. Khaibrakhmanov , Alexander E. Dudorov

During the lifetime of sun-like or low mass stars a significant amount of angular momentum is removed through magnetised stellar winds. This process is often assumed to be governed by the dipolar component of the magnetic field. However,…

Solar and Stellar Astrophysics · Physics 2018-03-22 Adam J. Finley , Sean P. Matt

We discuss results of global 3D MHD simulations of accretion on to a rotating magnetized star with a tilted dipole magnetic field, where the accretion is driven by the magneto-rotational instability (MRI). The simulations show that…

Solar and Stellar Astrophysics · Physics 2015-06-03 M. M. Romanova , G. V. Ustyugova , A. V. Koldoba , R. V. E. Lovelace

We study the steady-state structure of an accretion disc with a corona surrounding a central, rotating, magnetized star. We assume that the magneto-rotational instability is the dominant mechanism of angular momentum transport inside the…

Astrophysics · Physics 2009-06-23 Fazeleh Khajenabi , Mohsen Shadmehri , Sami Dib

We present the first results of a global axisymmetric simulation of accretion onto rotating magnetized stars from a turbulent, MRI-driven disk. The angular momentum is transported outward by the magnetic stress of the turbulent flow with a…

Solar and Stellar Astrophysics · Physics 2015-05-27 Marina M. Romanova , Galina V. Ustyugova , Alexander V. Koldoba , Richard V. E. Lovelace

A rapidly rotating and highly magnetized neutron star (NS) could be formed from the explosive phenomena such as superluminous supernovae and gamma-ray bursts. This newborn NS can substantially influence the emission of these explosive…

High Energy Astrophysical Phenomena · Physics 2021-02-10 Shao-Ze Li , Yun-Wei Yu , He Gao , Bing Zhang