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[7.02] Semiconvection in Massive Stars

I. Dobbs-Dixon, S. Woosley (UC Santa Cruz)

Results from one-dimensional simulations of semiconvective fluid mixing in massive stars are presented. The potential for mixing in classically stable (super-adiabatic, sub-Ledoux) regions has implications for stellar evolution, planetary interiors, and terrestrial processes. The degree of mixing changes the properties of both the gravitational potential and heat flow. We re-examine the definition of semiconvection and develop a model combining initial overstable oscillations in a thermally diffusive medium with a subsequent transition to layered convection as seen in the laboratory. Simulations utilize the formalism of One-Dimensional Turbulence initially developed by Kerstein (1999) for studying the statistical properties of turbulent fluid flow. This approach allows for an exploration of the wide range of both temporal and spatial scales inherent in in the problem but inaccessible to multidimensional techniques. Effective semiconvective diffusivities are calculated and applied to the evolution of massive stars.

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Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.