The sun as a star, an overview of the solar internal structure and evolution - ABSTRACT

Models of the solar interior form the basis for most helioseismic analyses. They are computed by following the solar evolution from an initial state, taking into account the changes in the composition structure resulting from nuclear reactions, microscopic diffusion and settling and convection and possibly other mixing processes. The model computations rely on a number of simplifications of possibly doubtful validity. Furthermore, they require information about the physical properties of solar matter, such as the equation of state, the opacity and the nuclear reaction rates. Comparing the result models with helioseismic inferences provides a test of the underlying assumptions and physics, and hence of their validity in computation of more general stellar models. In particular, it is possible to make detailed investigations of the properties of the equation of state. In addition to helioseismology, neutrinos resulting from the nuclear reactions in the solar core in principle provides information about the solar internal properties. A long-standing discrepancy between the predicted and measured flux of neutrinos has recently been resolved through the definite detection of transformations of neutrino types between the emission and detection.

Some preliminary reading

• Any of the several general books on stellar structure and evolution, such as: Hansen, C. J. & Kawaler, S. D., 1994. Stellar interiors. Physical principles, structure, and evolution. Springer, New York.
• Christensen-Dalsgaard, J., 2004. `An introduction to solar oscillations and helioseismology'. In Equation-of-State and Phase-Transition Issues in Models of Ordinary Astrophysical Matter, eds V. Celebonovic, W. Dappen & D. Gough, AIP Conf. Proc. vol. 731, AIP, Melville, New York, p. 18 - 46.
  A preprint is available here as PDF file and gzipped PS file.
• Chapter 11 of Christensen-Dalsgaard, J., 2004, Lecture Notes on Stellar Structure and Evolution, sixth edition, second printing.
  The chapter is available as a PDF file and a gzipped PS file.
• Christensen-Dalsgaard, J., 2002. `Helioseismology'. Rev. Mod. Phys., 74, 1073 - 1129. The paper is available here as PDF file.
• Extensive material on solar neutrinos can be found on John Bahcall's home page