  The creation of "hybrid" white dwarfs, made of a C-O core within a O-Ne shell
has been proposed, and studies indicate that ignition in the C-rich central
region makes these viable progenitors for thermonuclear (type Ia) supernovae.
Recent work found that the C-O core is mixed with the surrounding O-Ne as the
white dwarf cools prior to accretion, which results in lower central C
fractions in the massive progenitor than previously assumed. To further
investigate the efficacy of hybrid white dwarfs as progenitors of thermonuclear
supernovae, we performed simulations of thermonuclear supernovae from a new
series of hybrid progenitors that include the effects of mixing during cooling.
The progenitor white dwarf model was constructed with the one-dimensional
stellar evolution code MESA and represented a star evolved through the phase of
unstable interior mixing followed by accretion until it reached conditions for
the ignition of carbon burning. This MESA model was then mapped to a
two-dimensional initial condition for explosions simulated with FLASH. For
comparison, similar simulations were performed for a traditional C-O progenitor
white dwarf. By comparing the yields of the explosions, we find that, as with
earlier studies, the lower C abundance in the hybrid progenitor compared to the
traditional C-O progenitor leads to a lower average yield of 56Ni. Although the
unmixed hybrid WD showed a similar decrement also in total iron group yield,
the mixed case does not and produces a smaller fraction of iron group elements
in the form of 56Ni. We attribute this to the higher central density required
for ignition and the location, center or off-center, of deflagration ignition.
