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The effect of toroidal magnetic fields in the overshoot layer on the eigenfrequencies of stellar oscillations

Published online by Cambridge University Press:  03 August 2017

Gaetano Belvedere
Gaetano Belvedere*
Affiliation:
Istituto di Astronomia, Università di Catania, Italy

Abstract

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The overshoot layer in stellar convection zones is slightly subadiabatic and can be considered as a stable region for storage of magnetic flux. Belvedere, Pidatella and Stix (1986) estimated the size of the overshoot layer and computed the magnetic field strength, beyond which toroidal flux tubes become unstable to buoyancy, for a number of main sequence spectral types ranging from F5 to K0. Here we estimate the relative frequency perturbation of high order acoustic modes due to the presence of a non-oblique axisymmetric magnetic field in the overshoot layer. We find that increases with the advancing spectral type, the predicted frequency splitting being large enough to be detected by observations, at least for the Sun.

We conclude that magnetic field induced frequency splitting of high order acoustic modes may well be due to a toroidal field of relatively moderate strength just beneath the bottom of the convection zone.

Type
Chapter 2: Theory of Solar Oscillations
Information
Symposium - International Astronomical Union , Volume 123: Advances In Hello- and Asteroseismology , 1988 , pp. 167 - 170
Copyright
Copyright © Reidel 1988 

References

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