The physical structure of a nuclear flame is a basic ingredient of the theory of Type Ia supernovae ( SNIa ) .
Assuming an exponential density reduction with several characteristic times we have followed the evolution of a planar nuclear flame in an expanding background from an initial density 6.6 \times 10 ^ { 7 } g.cm ^ { -3 } down to 2 \times 10 ^ { 6 } g.cm ^ { -3 } .
The total amount of synthesized intermediate-mass elements ( IME ) , from silicon to calcium , was monitored during the calculation .
We have made use of the computed mass fractions , X _ { IME } , of these elements to give an estimation of the total amount of IME synthesized during the deflagration of a massive white dwarf .
Using X _ { IME } and adopting the usual hypothesis that turbulence decouples the effective burning velocity from the laminar flame speed , so that the relevant flame speed is actually the turbulent speed on the integral length-scale , we have built a simple geometrical approach to model the region where IME are thought to be produced .
It turns out that a healthy production of IME involves the combination of not too short expansion times , \tau _ { c } \geq 0.2 s , and high turbulent intensities .
According to our results it could be difficult to produce much more than 0.2 M _ { \sun } of intermediate-mass elements within the deflagrative paradigma .
The calculations also suggest that the mass of IME scales with the mass of Fe-peak elements , making it difficult to conciliate energetic explosions with low ejected nickel masses , as in the well observed SN1991bg or in SN1998de .
Thus a large production of Si-peak elements , especially in combination with a low or a moderate production of iron , could be better addressed by either the delayed detonation route in standard Chandrasekhar-mass models or , perhaps , by the off-center helium detonation in the sub Chandrasekhar-mass scenario .