Thermalization parameter η at the breakout time (t_lab = 0.3 s) for the canonical model. The blue, orange, and green curves correspond to θ = 1﹩\mathop{.}\limits^{{\unicode{x000b0}}}﹩0, 5﹩\mathop{.}\limits^{{\unicode{x000b0}}}﹩1, and 8﹩\mathop{.}\limits^{{\unicode{x000b0}}}﹩0, respectively. The dashed line marks η = 1, separating the LTE and non-LTE regimes. The jet frontier is at ∼6 × 10⁹ cm.