Gravity-wave polarization theory is extended to non-axisymmetric stellar magnetic fields, revealing avoided crossings and a new mixing threshold distinct from the magnetic-suppression threshold.
Asteroseismology Can Reveal Strong Internal Magnetic Fields in Red Giant Stars
8 Pith papers cite this work. Polarity classification is still indexing.
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Pith papers citing it
abstract
Internal stellar magnetic fields are inaccessible to direct observations and little is known about their amplitude, geometry and evolution. We demonstrate that strong magnetic fields in the cores of red giant stars can be identified with asteroseismology. The fields can manifest themselves via depressed dipole stellar oscillation modes, which arises from a magnetic greenhouse effect that scatters and traps oscillation mode energy within the core of the star. The Kepler satellite has observed a few dozen red giants with depressed dipole modes which we interpret as stars with strongly magnetized cores. We find field strengths larger than $\sim\! 10^5 \,{\rm G}$ may produce the observed depression, and in one case we infer a minimum core field strength of $\approx \! \! 10^7 \,{\rm G}$.
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First reported seismic detection of an internal magnetic field reaching approximately 4 kG in the radiative envelope of the gamma Doradus star KIC 2309579 using the variable delta Ka sensitive to Kelvin gravito-inertial modes.
1D models show convective boundary mixing dominates the asteroseismic imprint of accretion in massive stars, robust to semiconvection changes but drastically altered without it, with thermal relaxation as key.
Synthetic spectra show that observational biases cause dipole mode visibilities to be overestimated by up to 20 percent on the red-giant branch, while partial energy preservation under magnetic damping can produce both present and absent mixed-mode signatures.
A mean-field magnetic polytrope model shows radiation pressure can unbind an n=3 polytrope when the central overpressure exceeds roughly 0.15 times a mass-dependent factor under small radial perturbations.
MESA grids show global magnetic sensitivity in red giants depends on mass and metallicity and can be recovered to 10% uncertainty with accurate spectroscopic metallicity.
This review summarizes the development, techniques, and open questions in asteroseismology of solar-type stars whose oscillations are stochastically excited by surface convection.
Overview of asteroseismology principles, data needs, forward modeling methods, key results across the HR diagram, and future challenges.
citing papers explorer
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Extending asteroseismic magnetometry across the diverse landscape of magnetic structures
Gravity-wave polarization theory is extended to non-axisymmetric stellar magnetic fields, revealing avoided crossings and a new mixing threshold distinct from the magnetic-suppression threshold.
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Seismic signature of a magnetic field in the $\gamma$ Doradus star KIC 2309579
First reported seismic detection of an internal magnetic field reaching approximately 4 kG in the radiative envelope of the gamma Doradus star KIC 2309579 using the variable delta Ka sensitive to Kelvin gravito-inertial modes.
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The effect of near-core mixing on rejuvenation and the asteroseismic properties of massive accretors
1D models show convective boundary mixing dominates the asteroseismic imprint of accretion in massive stars, robust to semiconvection changes but drastically altered without it, with thermal relaxation as key.
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Oscillations of red giant stars with magnetic damping in the core. II. Mixed mode visibilities on the red-giant branch
Synthetic spectra show that observational biases cause dipole mode visibilities to be overestimated by up to 20 percent on the red-giant branch, while partial energy preservation under magnetic damping can produce both present and absent mixed-mode signatures.
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Non-linear Dynamical Stability of Magnetic Polytropes
A mean-field magnetic polytrope model shows radiation pressure can unbind an n=3 polytrope when the central overpressure exceeds roughly 0.15 times a mass-dependent factor under small radial perturbations.
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Constraining the model-based uncertainties of asteroseismic magnetic field measurements in red giants
MESA grids show global magnetic sensitivity in red giants depends on mass and metallicity and can be recovered to 10% uncertainty with accurate spectroscopic metallicity.
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Asteroseismology of solar-type stars
This review summarizes the development, techniques, and open questions in asteroseismology of solar-type stars whose oscillations are stochastically excited by surface convection.
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Asteroseismology
Overview of asteroseismology principles, data needs, forward modeling methods, key results across the HR diagram, and future challenges.