Wave Excitation in Disks Around Rotating Magnetic Stars

Abstract

The accretion disk around a rotating magnetic star (neutron star, white dwarf or T Tauri star) is subjected to periodic vertical magnetic forces from the star, with the forcing frequency equal to the stellar spin frequency or twice the spin frequency. This gives rise bending waves in the disk that may influence the variabilities of the system. We study the excitation, propagation and dissipation of these waves using a hydrodynamical model coupled with a generic model description of the magnetic forces. The $m=1$ bending waves are excited at the Lindblad/vertical resonance, and propagate either to larger radii or inward toward the corotation resonance where dissipation takes place. While the resonant torque is negligible compared to the accretion torque, the wave nevertheless may reach appreciable amplitude and can cause or modulate flux variabilities from the system. We discuss applications of our result to the observed quasi-periodic oscillations from various systems, in particular neutron star low-mass X-ray binaries.

arXiv commentSmall changes/clarifications. To be published in ApJ, Aug.20,2008 issue

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Cited by in corpus (14)

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• Warps, bending and density waves excited by rotating magnetized stars: results of global 3D MHD simulations
• Infrared Variability of Evolved Protoplanetary Disks: Evidence for Scale Height Variations in the Inner Disk
• Bipolar jets launched from accretion disks. II. Formation of symmetric and asymmetric jets and counter jets
• Theory of Disk Accretion onto Magnetic Stars
• Improved estimate of the detectability of gravitational radiation from a magnetically confined mountain on an accreting neutron star
• The Emergence of Negative Superhumps in Cataclysmic Variables: Smoothed Particle Hydrodynamics Simulations
• Corotational Damping of Diskoseismic C-modes in Black Hole Accretion Discs
• The Highly Dynamic Behavior of the Innermost Dust and Gas in the Transition Disk Variable LRLL 31
• Discovery of Drifting High-frequency QPOs in Global Simulations of Magnetic Boundary Layers
• Infrared Variability due to Magnetic Pressure Driven Jets, Dust Ejection and Quasi-Puffed-Up Inner Rims
• JWST captures a sudden stellar outburst and inner disk wall destruction
• Linear bending wave propagation in laminar and turbulent discs