Detecting axisymmetric magnetic fields using gravity modes in intermediate-mass stars

Context. Angular momentum (AM) transport models of stellar interiors require improvements to explain the strong extraction of AM from stellar cores that is observed with asteroseismology. One of the frequently invoked mediators of AM transport are internal magnetic fields, even though their properti...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2020-06, Vol.638, p.A149
Main Authors: Van Beeck, J., Prat, V., Van Reeth, T., Mathis, S., Bowman, D. M., Neiner, C., Aerts, C.
Format: Article
Language:English
Subjects:
Angular momentum
Astronomical models
Astrophysics
Computation
Field strength
Gravitation
Magnetic fields
Magnetic properties
Magnetic signatures
Main sequence stars
Oscillations
Parameters
Physics
Rotation
Stellar age
Stellar cores
Stellar evolution
Stellar interiors
Stellar magnetic fields
Stellar seismology
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Summary:Context. Angular momentum (AM) transport models of stellar interiors require improvements to explain the strong extraction of AM from stellar cores that is observed with asteroseismology. One of the frequently invoked mediators of AM transport are internal magnetic fields, even though their properties, observational signatures, and influence on stellar evolution are largely unknown. Aims. We study how a fossil, axisymmetric internal magnetic field affects period spacing patterns of dipolar gravity mode oscillations in main sequence stars with masses of 1.3, 2.0, and 3.0  M ⊙ . We assess the influence of fundamental stellar parameters on the magnitude of pulsation mode frequency shifts. Methods. We computed dipolar gravity mode frequency shifts due to a fossil, axisymmetric poloidal–toroidal internal magnetic field for a grid of stellar evolution models, varying stellar fundamental parameters. Rigid rotation was taken into account using the traditional approximation of rotation, and the influence of the magnetic field was computed using a perturbative approach. Results. We find magnetic signatures for dipolar gravity mode oscillations in terminal-age main sequence stars that are measurable for a near-core field strength larger than 10 5 G. The predicted signatures differ appreciably from those due to rotation. Conclusions. Our formalism demonstrates the potential for the future detection and characterization of strong fossil, axisymmetric internal magnetic fields in gravity-mode pulsators near the end of core-hydrogen burning from Kepler photometry, if such fields exist.
ISSN:0004-6361
1432-0746
1432-0756
DOI:10.1051/0004-6361/201937363