The 16 O( 3 He,d) 17 F reaction has been used to determine asymptotic normalization coefficients for transitions to the ground and first excited states of 17 F. The coefficients provide the normalization for the tails of the overlap functions for 17 F→ 16 Oϩp and allow us to calculate the S factors for 16 O(p,␥) 17 F at astrophysical energies. The calculated S factors are compared to measurements and found to be in very good agreement. This provides a test of this indirect method to determine astrophysical direct capture rates using transfer reactions. In addition, our results yield S(0) for capture to the ground and first excited states in 17 F, without the uncertainty associated with extrapolation from higher energies. ͓S0556-2813͑99͒00702-5͔ PACS number͑s͒: 25.40. Lw, 25.55.Hp, 26.20.ϩf, 27.20.ϩn

The 15 N(p, γ ) 16 O reaction provides a path from the CN cycle to the CNO bi-cycle and CNO tri-cycle. The measured astrophysical factor for this reaction is dominated by resonant capture through two strong 16 O reaction. The results indicate that the direct capture contribution was previously overestimated. We find the astrophysical factor to be S(0) = 36.0 ± 6.0 keV b, which is about a factor of 2 lower than the presently accepted value. We conclude that for every 2200 ± 300 cycles of the main CN cycle one CN catalyst is lost due to this reaction.

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