Evolution of the temperature of a burning convective bubble as a function of the distance to the center of the white dwarf, for different initial temperatures, T₀, and prescriptions for the ¹²C+¹²C rate. From top to bottom: CF88 (short-long dashed line), LER-1.5-0.001-1.0 (dot-long dashed line), LER-1.5-0.1-1.0 (solid line), and LER-1.5-10.-1.0 (long-dashed line). For each reaction rate, we followed the evolution of the bubbles starting at the center, r = 0, with different trial initial temperatures, until we found the minimum initial temperature leading to runaway of the bubble before reaching the end of the convective core. The distance to the center varies linearly with the elapsed time, r = r₀ + v_convt, where v_conv = 80 km s^-1 is the convective velocity. To test the impact of the off-center ignition (at R_rw ~ 149 km) in model LER-1.5-10.-1.0, we computed the bubble evolution with the same rate but starting from the center. The runaway temperature, shown by the thin long-dashed line, is nearly the same as in the off-center calculation of the same model.