Dynamics of magnetic flux tubes in accretion disks of Herbig Ae/Be stars

The dynamics of magnetic flux tubes (MFTs) in the accretion disk of typical Herbig Ae/Be star with fossil large-scale magnetic field is modeled taking into account the buoyant and drag forces, radiative heat exchange with the surrounding gas, and the magnetic field of the disk. The structure of the...

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Bibliographic Details
Published inarXiv.org
Main Authors Khaibrakhmanov, Sergey A, Dudorov, Alexander E
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 09.02.2022
Subjects
Accretion disks
B stars
Drag
Fluid flow
Heat exchange
Magnetic fields
Magnetic flux
Magnetohydrodynamics
Stellar magnetic fields
Stellar oscillations
Stellar radiation
Surface layers
T Tauri stars
Tubes
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Summary:The dynamics of magnetic flux tubes (MFTs) in the accretion disk of typical Herbig Ae/Be star with fossil large-scale magnetic field is modeled taking into account the buoyant and drag forces, radiative heat exchange with the surrounding gas, and the magnetic field of the disk. The structure of the disk is simulated using our magnetohydrodynamic (MHD) model, taking into account the heating of the surface layers of the disk with the stellar radiation. The simulations show that MFTs periodically rise from the innermost region of the disk with speeds up to \(10-12\) km s\(^{-1}\). MFTs experience decaying magnetic oscillations under the action of the external magnetic field near the disk's surface. The oscillation period increases with distance from the star and initial plasma beta of the MFT, ranging from several hours at \(r=0.012\) au up to several months at \(r=1\) au. The oscillations are characterized by pulsations of the MFT's characteristics including its temperature. We argue that the oscillations can produce observed IR-variability of Herbig Ae/Be stars, which would be more intense than in the case of T Tauri stars, since the disks of Herbig Ae/Be stars are hotter, denser and have stronger magnetic field.
ISSN:2331-8422