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Étude approfondie de la structure interne du Soleil: héliosismologie et modèles fins incluant la ségrégation détaillée des éléments et les processus de transport

Abstract : In this thesis we have studied different aspects of modelling the solar internal structure. The accuracy of Helioseismology gives strong constraints on the structure of solar models. The best standard models (models where convection and microscopic diffusion are the only transport processes taken into account) reproduce the sound speed of the seismic Sun (obtained by inversion of seismic modes) with a deviation smaller than 1%. With such an accuracy we tested the effects on the models of variations in the quantities used for their calibration, inside their error bars. We have noted that these variations give negligible changes in the comparison with the sound speed of the seismic Sun. We have studied the accuracy on the helioseismic determination of the solar helium abundance. We also have studied the effects of modifications in the input physics (equation of state, opacities, nuclear reaction rates and initial mixture) on the structure of models. Our best model, obtained with the most recent data, reproduces the sound velocity of the seismic Sun within 0.3%. We have studied several physical processes able to reproduce the helioseismic and chemical constraints: mass loss, mixing processes and temperature fluctuations that could occur at the bottom of the convective zone. We have shown that the rotation-induced mixing could reproduce the chemical constraints while improving the agreement with the seismic Sun. All the models predict neutrino fluxes more important than those observed. We have tested a mixing that could occur in the solar core and reduce the neutrino fluxes: it destroys the agreement with the seismic Sun. These results seem to show that the solution of the solar neutrino problem is in particle physics.
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https://tel.archives-ouvertes.fr/tel-00004294
Contributor : Olivier Richard <>
Submitted on : Friday, January 23, 2004 - 12:52:18 PM
Last modification on : Thursday, October 15, 2020 - 4:06:52 AM
Long-term archiving on: : Friday, April 2, 2010 - 7:16:37 PM

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  • HAL Id : tel-00004294, version 1

Citation

Olivier Richard. Étude approfondie de la structure interne du Soleil: héliosismologie et modèles fins incluant la ségrégation détaillée des éléments et les processus de transport. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 1999. Français. ⟨tel-00004294⟩

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