Measurement of F 19 ( p ,   α γ ) O 16 Reaction Reopens the Fluorine Conundrums in Stars

Fluorine abundance in stars is a sensitive indicator of the physical conditions and processes occurring within their interiors. Recent extrapolated results on the ^{19}F(p,αγ)^{16}O fluorine destruction cross section suggested an increase of the astrophysical factor by several orders of magnitude at astrophysical energies, with profound implications for our understanding of stellar evolution and nucleosynthesis. We have indirectly measured the ^{19}F(p,αγ)^{16}O cross section using the Trojan horse method, fully covering astrophysical energies with no need of extrapolations. The strength of the 11 keV resonance was extracted and a significant reduction of the reaction rate was determined, compared to previous studies. The analysis of the astrophysical impact suggests that our measurement challenges existing predictions about fluorine and heavier elements' abundances, reigniting unresolved questions in the field.