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Background: Shell hydrogen burning during the asymptotic giant branch (AGB) phase through oxygen isotopes has been indicated as a key process that is needed to understand observed O18/O16 relative abundance in presolar grains and stellar atmospheres. This ratio strongly influenced by strengths of reactions O18(p,α)N15 O18(p,γ)F19 low-mass AGB stars. While former channel focus large number measurements, (p,γ) reaction path only recently received some attention its rate over wide temperature range rests on one measurement. Purpose: Our aim direct measurement states F19 populated better determine their influence astrophysical rate, more generally improve understanding nuclear structure F19. Method: Branchings resonance were measured proton energy Eplab=150–400keV, using high-purity germanium detector inside massive lead shield. The took place ultra-low-background environment Laboratory for Underground Nuclear Astrophysics (LUNA) experiment at Gran Sasso National Laboratory, leading highly increased sensitivity. Results: uncertainty γ branchings was improved all four resonances studied range; many new transitions case 334keV resonance, individual decays 215keV first time. In addition intermediate decay α emission identified. are agreement with literature values. Conclusions: measurements substantially confirm previous determinations relevant strengths. Therefore does not change respect reported compilations commonly adopted extant computations red-giant models. Nevertheless, our definitely exclude nonstandard scenario fluorine nucleosynthesis physics solution O18 depletion Group 2 oxygen-rich stardust grains.3 MoreReceived 18 June 2020Revised 12 April 2021Accepted 6 July 2021DOI:https://doi.org/10.1103/PhysRevC.104.025802©2021 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasH & He burningNuclear astrophysicsNuclear reactionsRadiative captureProperties6 ≤ A 19Nuclear Physics