Résumé : In explosive stellar hydrogen burning, the hot CNO cycles and the rp-process are mainly linked by the reaction sequence 15O(α, γ)19Ne(p,γ)20Na. Using intense 19Ne radioactive beams, both the 19Ne(p,γ) and the 19Ne(d,n) reaction have been studied. Upper and lower limits for the 19Ne(p,γ) reaction rate have been deduced, allowing to conclude that the 15O(α,γ) reaction is most likely the bottleneck reaction.