Slow rotation of the Sun's interior

Elsworth, Y.; Howe, R.; Isaak, G. R.; McLeod, C. P.; Miller, B. A.; New, R.; Wheeler, S. J.; Gough, D. O.

doi:10.1038/376669a0

Cited by 115 publications

(85 citation statements)

References 12 publications

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“…Indeed, although the results are consistent with constant rotation in the radiative interior, it is tempting to speculate about the possibility of a slowly rotating core, relative to the rest of the radiative zone. Indications of slow core rotation, also based on BiSON data, had previously been found by Elsworth et al (1995), while Corbard et al (1997) and Eff-Darwich, Korzennik, & Jimenez-Reyes (2002) found a similar tendency from analyses of LOWL, and LOWL, GONG and MDI, data respectively. It should be pointed out, however, that the rotation of the deep solar interior is still uncertain, different datasets yielding rather different results, although none showing the rapid rotation that had been predicted theoretically (for a review, see Eff-Darwich & .…”

Section: The Solar Internal Rotationsupporting

confidence: 54%

The Internal Solar Rotation from Helioseismology

Christensen‐Dalsgaard

2004

Symp. - Int. Astron. Union

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Helioseismology has provided detailed inferences about the internal rotation of the Sun, and hence stringent constraints on any attempt to understand the properties and evolution of stellar rotation. Here I briefly discuss the techniques used in the analysis and review the results that have been obtained. Strikingly, these results are markedly different from the predictions made before the helioseismic data became available, emphasizing the difficulties in the modelling of phenomena as complex as stellar internal rotation.

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Section: The Solar Internal Rotationsupporting

confidence: 54%

The Internal Solar Rotation from Helioseismology

Christensen‐Dalsgaard

2004

Symp. - Int. Astron. Union

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“…In our model, the core is rotating faster than the rest of the radiative interior. However, helioseismic results show the solar core is rotating more slowly than the rest of the radiative interior (Chaplin et al 1999;Elsworth et al 1995;Tomczyk et al 1995), or else it is a solid-body rotation (Charbonneau et al 1998). Some mechanism of angular momentum transport may be missed, or the value of B r /B should be larger than the one used in the core in our model.…”

Section: Transport Of Angular Momentummentioning

confidence: 99%

Angular momentum transport and element mixing in the stellar interior

Yang

2006

A&A

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Aims. The purpose of this work was to obtain diffusion coefficient for the magnetic angular momentum transport and material transport in a rotating solar model. Methods. We assumed that the transport of both angular momentum and chemical elements caused by magnetic fields could be treated as a diffusion process. Results. The diffusion coefficient depends on the stellar radius, angular velocity, and the configuration of magnetic fields. By using of this coefficient, it is found that our model becomes more consistent with the helioseismic results of total angular momentum, angular momentum density, and the rotation rate in a radiative region than the one without magnetic fields. Not only can the magnetic fields redistribute angular momentum efficiently, but they can also strengthen the coupling between the radiative and convective zones. As a result, the sharp gradient of the rotation rate is reduced at the bottom of the convective zone. The thickness of the layer of sharp radial change in the rotation rate is about 0.036 R in our model. Furthermore, the difference of the sound-speed square between the seismic Sun and the model is improved by mixing the material that is associated with angular momentum transport.

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“…15). The solar rotational profile is known in great detail for only those regions probed by pressure-dominated modes [16][17][18] . In contrast to these modes in the wings of the dipole forest, only 30% of the splitting of the centre mode originates from the central region of the star, whereas the outer third by mass of the star contributes 50% of the frequency splitting.…”

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confidence: 99%

Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes

Beck

Montalbán

Kallinger

et al. 2011

Nature

488

544

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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. Convection takes place over much of the star's radius. Conservation of angular momentum requires that the cores of these stars rotate faster than their envelopes; indirect evidence supports this 1,2 . 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 an increasing rotation rate from the surface of the star to the stellar core in the interiors of red giants, obtained using the rotational frequency splitting of recently detected 'mixed modes' 3,4 . By comparison 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 1,5,6 .The asteroseismic approach to studying stellar interiors exploits information from oscillation modes of different radial order n and angular degree l, which propagate in cavities extending at different depths 7 . Stellar rotation lifts the degeneracy of non-radial modes, producing a multiplet of (2l 1 1) frequency peaks in the power spectrum for each mode. The frequency separation between two mode components of a multiplet is related to the angular velocity and to the properties of the mode in its propagation region. More information on the exploitation of rotational splitting of modes may be found in the Supplementary Information. An important new tool comes from mixed modes that were recently identified in red giants 3,4 . Stochastically excited solar-like oscillations in evolved G and K giant stars 8 have been well studied in terms of theory [9][10][11][12] , and the main results are consistent with recent observations from space-based photometry 13,14 . Whereas pressure modes are completely trapped in the outer acoustic cavity, mixed modes also probe the central regions and carry additional information from the core region, which is probed by gravity modes. Mixed dipole modes (l 5 1) appear in the Fourier power spectrum as dense clusters of modes around those that are best trapped in the acoustic cavity. These clusters, the components of which contain varying amounts of influence from pressure and gravity modes, are referred to as 'dipole forests'.We present the Fourier spectra of the brightness variations of stars KIC 8366239 (Fig. 1a), KIC 5356201 ( Supplementary Fig. 3a) and KIC 12008916 ( Supplementary Fig. 5a), derived from observations with the Kepler spacecraft. The three spectra show split modes, the spherical degree of which we identify as l 5 1. These detected multiplets cannot have been caused by finite mode lifetime effects from mode damping, because that would not lead to a consistent multiplet appearance over several orders such as that shown in Fig. 1. ...

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Slow rotation of the Sun's interior

Cited by 115 publications

References 12 publications

The Internal Solar Rotation from Helioseismology

The Internal Solar Rotation from Helioseismology

Angular momentum transport and element mixing in the stellar interior

Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes

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