Effects of boundary conditions and viscous energy dissipation on carbon burning in thermonuclear supernova models |
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| Authors: | N V Dunina-Barkovskaya V S Imshennik |
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| Institution: | (1) Institute of Theoretical and Experimental Physics, ul. Bol'shaya Cheremushkinskaya 25, Moscow, 117259, Russia |
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| Abstract: | Based on a one-dimensional hydrodynamic model, we investigate carbon burning in a thermonuclear type-Ia supernova in the approximation of unsteady convection. The relatively broad range of convective parameters, 1×10?3≤αc≤2×10?3, in which delayed detonation from the edge takes place was found to be preserved only for cases with a low boundary temperature at the presupernova stage, T b (PS) = 6.4 × 106 K, and with a high envelope mass, mex ? 2 × 10?3M⊙. In cases with a more realistic temperature, T b (PS) = 2 × 108 K, which corresponds to helium burning in the shell source, and with a lower mass mex, delayed detonation from the edge takes place only at αc = 2 × 10?3, while at αc = 1 × 10?3, numerous model pulsations occur during t?500 s. Artificial viscosity is shown to give a determining contribution to the increase in entropy in outer model shells, which is caused by the generation of weak shock waves during pulsations. We also show that the entropies calculated by two independent methods are equal. |
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| Keywords: | supernovae and supernova remnants plasma astrophysics hydrodynamics and shock waves detonation and deflagration |
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