Laminar flame acceleration by neon-22 enrichment in white dwarf supernovae

We explore how the laminar flame speed of degenerate C/O thermonuclear burning during a type Ia supernova depends on the composition of the white dwarf. Type Ia supernovae are currently the premier standard candle for measuring distances to redshift ≲1.6. The currently favored scenario for this supernovae is the thermonuclear incineration of a C/O white dwarf. Recent observations suggest that there may be more than one population of progenitor, and it has been suggested the peak luminosity may depend on the composition of the progenitor white dwarf. Of particular interest is ²²Ne, which is formed from CNO elements during core He burning of the progenitor star and therefore reflects the metallicity of the progenitor. We find that the laminar flame speed of a C/O mixture increases linearly with the abundance of ²²Ne when the abundance of ²²Ne is small. The faster and narrower laminar flame enlarges the lengthscale at which turbulent eddies can disrupt the burn. As a result, the addition of ²²Ne might lower the density at which a transition to distributed burning occurs.