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Using a rotating flat layer heated from below as an example, we consider effects which lead to stabilizing an exponentially growing magnetic field in magnetostrophic convection in transition from the kinematic dynamo to the full non-linear…

Fluid Dynamics · Physics 2015-05-18 P. Hejda , M. Reshetnyak

At second order in perturbation theory, the $r$-modes of uniformly rotating stars include an axisymmetric part that can be identified with differential rotation of the background star. If one does not include radiation-reaction, the…

High Energy Astrophysical Phenomena · Physics 2018-03-07 John L. Friedman , Lee Lindblom , Keith H. Lockitch

In this brief note, we clarify certain aspects related to the magnetic (i.e., odd parity or axial) tidal Love numbers of a star in general relativity. Magnetic tidal deformations of a compact star had been computed in 2009 independently by…

General Relativity and Quantum Cosmology · Physics 2018-12-20 Paolo Pani , Leonardo Gualtieri , Tiziano Abdelsalhin , Xisco Jiménez Forteza

We calculate axisymmetric oscillations of rotating neutron stars composed of the surface fluid ocean, solid crust, and fluid core, taking account of a dipole magnetic field as strong as $B_S\sim 10^{15}$G at the surface. The adiabatic…

Astrophysics · Physics 2008-11-26 Umin Lee

Differential rotation plays a crucial role in the alpha-omega dynamo, and thus also in creation of magnetic fields in stars with convective outer envelopes. Still, measuring the radial differential rotation on stars is impossible with the…

Astrophysics · Physics 2009-11-13 H. Korhonen , D. Elstner

We generalize the Rigid-Field Hydrodynamic equations to accommodate arbitrary magnetic field topologies, resulting in a new Arbitrary Rigid-Field hydrodynamic (ARFHD) formalism. We undertake a critical point calculation of the steady-state…

Solar and Stellar Astrophysics · Physics 2016-08-01 Christopher Bard , Richard H. D. Townsend

We present three-dimensional simulations of the dynamical bar-mode instability in magnetized and differentially rotating stars in full general relativity. Our focus is on the effects that magnetic fields have on the dynamics and the onset…

General Relativity and Quantum Cosmology · Physics 2015-06-16 Luca Franci , Roberto De Pietri , Kyriaki Dionysopoulou , Luciano Rezzolla

The interaction of differential rotation and toroidal fields that are current-free in the gap between two corotating axially unbounded cylinders is considered. It is shown that nonaxisymmetric perturbations are unstable if the rotation rate…

Solar and Stellar Astrophysics · Physics 2015-06-15 G. Ruediger , M. Gellert , M. Schultz , R. Hollerbach , F. Stefani

Rotation contributes to internal mixing processes and observed variability in massive stars. A significant number of binary stars are not in strict synchronous rotation, including all eccentric systems. This leads to a tidally induced and…

Solar and Stellar Astrophysics · Physics 2021-09-29 Gloria Koenigsberger , Edmundo Moreno , Norbert Langer

Non-axisymmetric oscillations of differentially rotating stars are studied using both slow rotation and Cowling approximation. The equilibrium stellar models are relativistic polytropes where differential rotation is described by the…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Andrea Passamonti , Adamantios Stavridis , Kostas Kokkotas

We present long-term (~10^4 M) axisymmetric simulations of differentially rotating, magnetized neutron stars in the slow-rotation, weak magnetic field limit using a perturbative metric evolution technique. Although this approach yields…

Astrophysics · Physics 2009-11-11 Zachariah B. Etienne , Yuk Tung Liu , Stuart L. Shapiro

We consider the general problem of a Parker-type non-relativistic isothermal wind from a rotating and magnetic star. Using the magnetohydrodynamics (MHD) code athena++, we construct an array of simulations in the stellar rotation rate…

Solar and Stellar Astrophysics · Physics 2023-11-01 Matthias J. Raives , Matthew S. B. Coleman , Todd A. Thompson

We further develop the Tayler--Spruit dynamo theory, based on the most efficient instability for generating magnetic fields in radiative layers of differentially rotating stars. We avoid the simplifying assumptions that either the $\mu$--…

Astrophysics · Physics 2009-11-10 Andre Maeder , Georges Meynet

A crucial missing ingredient in previous theoretical studies of fragmentation is the inclusion of dynamically important levels of magnetic fields. As a minimal model for a candidate presursor to the formation of binary and multiple stars,…

Astrophysics · Physics 2007-05-23 D. Galli , F. H. Shu , G. Laughlin , S. Lizano

An investigation is made of disk accretion of matter onto a rotating star with an aligned dipole magnetic field. A new aspect of this work is that when the angular velocity of the star and disk differ substantially we argue that the $\bf B$…

Astrophysics · Physics 2015-06-24 R. V. E. Lovelace , M. M. Romanova , G. S. Bisnovatyi-Kogan

Relativistic stars are endowed with intense electromagnetic fields but are also subject to oscillations of various types. We here investigate the impact that oscillations have on the electric and magnetic fields external to a relativistic…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Luciano Rezzolla , Bobomurat J. Ahmedov

Violation of the axial synnetry of a magnetic field essentially modifies the physics of the plasma outflow in the magnetosphere of rotating objects. In comparison to the axisymmetric outflow, two new affects appear: more efficient…

Astrophysics · Physics 2009-10-31 S. V. Bogovalov

We perform the first magnetohydrodynamical simulations of tidal disruptions of stars by supermassive black holes. We consider stars with both tangled and ordered magnetic fields, for both grazing and deeply disruptive encounters. When the…

High Energy Astrophysical Phenomena · Physics 2017-01-18 James Guillochon , Michael McCourt

The energy dissipation of wave-like tidal flows in the convective envelope of low-mass stars is one of the key physical mechanisms that shape the orbital and rotational dynamics of short-period planetary systems. Tidal flows, and the…

Tidal dissipation in stars is one of the key physical mechanisms that drive the evolution of binary and multiple stars. As in the Earth oceans, it corresponds to the resonant excitation of their eigenmodes of oscillation and their damping.…

Solar and Stellar Astrophysics · Physics 2015-06-23 P. Auclair-Desrotour , S. Mathis , C. Le Poncin-Lafitte