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.
Fast core rotation in red-giant stars revealed by gravity-dominated mixed modes
3 Pith papers cite this work. Polarity classification is still indexing.
abstract
When the core hydrogen is exhausted during stellar evolution, the central region of a star contracts and the outer envelope expands and cools, giving rise to a red giant, in which convection occupies a large fraction of the star. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes, and indirect evidence supports this. Information about the angular momentum distribution is inaccessible to direct observations, but it can be extracted from the effect of rotation on oscillation modes that probe the stellar interior. Here, we report the detection of non-rigid rotation in the interiors of red-giant stars by exploiting the rotational frequency splitting of recently detected mixed modes. We demonstrate an increasing rotation rate from the surface of the star to the stellar core. Comparing with theoretical stellar models, we conclude that the core must rotate at least ten times faster than the surface. This observational result confirms the theoretical prediction of a steep gradient in the rotation profile towards the deep stellar interior.
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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.
A review summarizing formation-channel predictions, waveform effects, and population-level constraints on stellar-mass black hole spins from the first decade of gravitational-wave observations.
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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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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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The first decade of gravitational-wave measurements of black hole spins
A review summarizing formation-channel predictions, waveform effects, and population-level constraints on stellar-mass black hole spins from the first decade of gravitational-wave observations.