Same as Fig. 2. Left panel: results of [Eu/Fe] vs [Fe/H] for model HC0. This model is identical to model M11. We plot it again to emphasise the consequences of the variation of α_NS. Central panel: same as left panel but for model HC1. In this case α_NS = 0.01. To maintain constant the total amount of produced Eu, we reduce to 8.0 × 10⁻⁶ M_⊙. Right panel: same as left panel but for model HC2 (α_NS = 0.02 and  = 4.0 × 10⁻⁶ M_⊙).