Does Betelgeuse have a magnetic field?

Recent numerical simulations by Freytag et al. of the outer convection envelope of the cool super-giant Betelgeuse, have shown that the fluctuations in the star's apparent luminosity may be caused by giant cell convection. These simulations bring forth the possibility of addressing another ques...

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Bibliographic Details
Published inarXiv.org
Main Authors Dorch, S B F, Freytag, B
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 29.08.2002
Subjects
Computer simulation
Convection cooling
Luminosity
Magnetic fields
Red giant stars
Rotating generators
Simulation
Supergiant stars
Variations
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Summary:Recent numerical simulations by Freytag et al. of the outer convection envelope of the cool super-giant Betelgeuse, have shown that the fluctuations in the star's apparent luminosity may be caused by giant cell convection. These simulations bring forth the possibility of addressing another question; namely whether stars such as Betelgeuse may harbor magnetic activity. Taking the detailed numerical simulations of the star at face value, we have applied a kinematic dynamo analysis, to study whether the flow field of the super-giant may be able to amplify a weak seed magnetic field. We do indeed find a positive exponential growth rate of the magnetic energy. The possible Betelgeusian dynamo may be characterized as belonging to the class of so-called ``local small-scale dynamos'' (i.e. dynamos where rotation is not dominant), but this is a less meaningful designation in the case of Betelgeuse, since the field is both global and large-scale.
ISSN:2331-8422