Cococubed.com Laminar Flame Speedup By Neon-22
Home Commercial: Artwork Software Teaching materials Bicycle sag support Free: Family Album Pretty astronomy pictures Some astronomy codes Some astronomy talks Some research ... Fallback ... Ti44 + Ni56 ... He shell flash ... SNIa ignition ... Flames with 22Ne ... P-rich NSE ... Verification Bicycle adventures Contact us: J.D. Maldonado F.X.Timmes, my vitae	Some new work with David Chamulak and Ed Brown. Carbon-oxygen white dwarfs contain 22Ne formed from alpha-captures onto 14N during core He burning in the progenitor star. In a white dwarf (type Ia) supernova, the 22Ne abundance determines, in part, the neutron-to-proton ratio and hence the abundance of radioactive 56Ni that powers the lightcurve. The 22Ne abundance also changes the burning rate and hence the laminar flame speed. We tabulate the flame speedup for different initial 12C and 22Ne abundances and for a range of densities. This increase in the laminar flame speed - about 30% for a 22Ne mass fraction of 6% - affects the deflagration just after ignition near the center of the white dwarf, where the laminar speed of the flame dominates over the buoyant rise, and in regions of lower density ~ 10**7 g/cc where a transition to distributed burning is conjectured to occur. The increase in flame speed will decrease the density of any transition to distributed burning. Fig. 1 - Flame speeds computed with an 130-nuclide network (dashed line) and a 430-nuclide network (dash-dotted line). We compare these with the results of Timmes and Woosley (1992, dotted line), and our fit formula. Our 130-nuclide network uses the same nuclides as Timmes and Woosley. Fig 2 - Abundances of selected nuclides during a burn at density=2.0e9 g/cc and with an initial carbon mass fraction of 0.3. We show runs with an initial Ne22 abundance of 0.06 (solid lines) and 0.0 (dashed lines). A much more detailed table than what is found in the printed journal article may be found here on Ed Brown's web site. Unpublished figures: Thermal transport in a laminar flame propagating at 83.3 km/s into a X(12C)=0 X(O16)=0.5 mixture at a density of 2.0e9 g/cc. The origin of the spatial coordinate is at the maximum of the flux |K dT/dx|, and the two dotted vertical lines delimit the region where |KdT/dx| > 0.5 max(|KdT/dx|). We plot the total thermal conductivity (left-hand axis, solid line) and its contributions from degenerate electrons (dashed line) and radiative transport (dotted line). The ratio of the electron plasma temperature to the gas and radiation temperature is shown as well (right-hand axis, dash-dotted line). Thermal transport in a laminar flame propagating at 28.4 km/s into a X(12C)=0 X(O16)=0.5 mixture at a density of 5.0e8 gr/cc. The lines have the same meaning as the figure to the left. The Ne22 lifetime becomes less than the C12 lifetime once the alpha abundance is greater than 1.0e-4. Isotopes, 1.0e8 gr/cc density, X(C12)=0.3, X(Ne22)=0.0 Thermodynamics, 1.0e8 gr/cc density, X(C12)=0.3, X(Ne22)=0.0 Thermodynamics, 1.0e8 gr/cc density, X(C12)=0.5, X(Ne22)=0.0 Thermodynamics, 1.0e8 gr/cc density, X(C12)=0.5, X(Ne22)=0.06