Proton capture on ${}^{17}$O and its astrophysical implications

Proton capture on $^{17}$ O and its astrophysical implications

A. Kontos, J. Görres, A. Best, M. Couder, R. deBoer, G. Imbriani, Q. Li, D. Robertson, D. Schürmann, E. Stech, E. Uberseder, and M. Wiescher

Phys. Rev. C 86, 055801 – Published 5 November 2012; Erratum Phys. Rev. C 88, 029905 (2013)

Abstract

Background: The reaction $^{17}$ O ${(p, γ)}^{18}$ F influences hydrogen-burning nucleosynthesis in several stellar sites, such as red giants, asymptotic giant branch (AGB) stars, massive stars, and classical novae. In the relevant temperature range for these environments ( $T_{9} = 0.01$ – $0.4$ ), the main contributions to the rate of this reaction are the direct capture process, two low-lying narrow resonances ( $E_{r} = 65.1$ and 183 keV) and the low-energy tails of two broad resonances ( $E_{r} = 557$ and 677 keV).

Purpose: Previous measurements and calculations give contradictory results for the direct capture contribution which in turn increases the uncertainty of the reaction rate. In addition, very few published cross section data exist for the high energy region that might affect the interpretation of the direct capture and the contributions of the broad resonances in the lower energy range. This work aims to address these issues.

Method: The reaction cross section was measured in a wide proton energy range ( $E_{c . m .} = 345$ –1700 keV) and at several angles ( $θ_{lab} = 0^{\circ}, 45^{\circ}, 90^{\circ}, 135^{\circ}$ ). The observed primary $γ$ transitions were used as input in an $R$ -matrix code in order to obtain the contribution of the direct capture and the two broad resonances to the low-energy region.

Results: The extrapolated $S$ factor from the present data is in good agreement with the existing literature data in the low-energy region. A new reaction rate was calculated from the combined results of this work and literature $S$ -factor determinations. Resonance strengths and branchings are reported for several $^{18}$ F states.

Conclusions: We were able to extrapolate the astrophysical $S$ factor of the reaction $^{17}$ O ${(p, γ)}^{18}$ F at low energies from cross section data taken at higher energies. No significant changes in the nucleosynthesis are expected from the newly calculated reaction rate.

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Received 17 July 2012

DOI:https://doi.org/10.1103/PhysRevC.86.055801

Erratum

Erratum: Proton capture on $^{17} O$ and its astrophysical implications [Phys. Rev. C 86, 055801 (2012)]

A. Kontos, J. Görres, A. Best, M. Couder, R. deBoer, G. Imbriani, Q. Li, D. Robertson, D. Schürmann, E. Stech, E. Uberseder, and M. Wiescher

Phys. Rev. C 88, 029905 (2013)

Authors & Affiliations

A. Kontos^1,2,*, J. Görres^1,2, A. Best^1,2,†, M. Couder^1,2, R. deBoer^1,2, G. Imbriani^2,3, Q. Li^1,2, D. Robertson^1,2, D. Schürmann^2,‡, E. Stech^1,2, E. Uberseder^1,2, and M. Wiescher^1,2

¹Department of Physics, University of Notre Dame, Notre Dame, Indiana 46556, USA
²The Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, Indiana 46556, USA
³Dipartimento di Scienze Fisiche, Università Federico II, and INFN Sezione di Napoli, Naples, Italy

^*Present address: National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA; kontos@nscl.msu.edu
^†Present address: Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
^‡Present address: Dipartimento di Scienze Fisiche, Università Federico II, Naples, Italy.

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Vol. 86, Iss. 5 — November 2012

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