17O(α,γ)21Ne and17O(α, n)20Ne for the weak s process

Go?rres, J.; Gu?ray, R. T.; O?zkan, N.; Best, A.; Görres, J.; Beard, M.; Couder, M.; deBoer, R.; Falahat, S.; Güray, R. T.; Kontos, A.; Kratz, K.-L.; LeBlanc, P. J.; Li, Q.; O'Brien, S.; Özkan, N.; Pignatari, M.; Sonnabend, K.; Talwar, R.; Tan, W.; Uberseder, E.; Wiescher, M.

Abstract

The ratio of the reaction rates of the competing channels 17 O(αγ) 21 Ne and 17 O(α,n) 20 Ne determines the efficiency of 16 O as a neutron poison in the s process in low metallicity rotating stars. It has a large impact on the element production, either producing elements to the mass range of A=90 in case of a significant poisoning effect or extending the mass range up to the region of A=150 if the γ channel is of negligible strength. We present an improved study of the reaction 17 O(α,n) 20 Ne, including an independent measurement of the 17 O(α,n 1 ) 20 Ne channel. A simultaneous R-Matrix fit to both the n 0 and the n 1 channels has been performed. New reaction rates, including recent data on the 17 O(α,γ) 21 Ne reaction, have been calculated and used as input for stellar network calculations and their impact on the s process in rotating massive stars is discussed. © 2012 American Institute of Physics.

Citation

Best, A., Görres, J., Beard, M., Couder, M., deBoer, R., Falahat, S., Güray, R. T., Kontos, A., Kratz, K.-L., LeBlanc, P. J., Li, Q., O'Brien, S., Özkan, N., Pignatari, M., Sonnabend, K., Talwar, R., Tan, W., Uberseder, E., & Wiescher, M. 17O(α,γ)21Ne and17O(α, n)20Ne for the weak s process. Presented at EXOTIC NUCLEI AND NUCLEAR/PARTICLE ASTROPHYSICS (IV). FROM NUCLEI TO STARS: Carpathian Summer School of Physics 2012, Sinaia, Romania

• Presentation Conference Type: Conference Paper (published)
• Conference Name: EXOTIC NUCLEI AND NUCLEAR/PARTICLE ASTROPHYSICS (IV). FROM NUCLEI TO STARS: Carpathian Summer School of Physics 2012
• Acceptance Date: Jan 1, 2012
• Online Publication Date: Dec 1, 2012
• Publication Date: Dec 1, 2012
• Deposit Date: Oct 30, 2018
• Journal: AIP Conference Proceedings
• Print ISSN: 0094-243X
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 1498
• Pages: 309-313
• ISBN: 9780735411128
• DOI: https://doi.org/10.1063/1.4768509
• Keywords: Helium burning; Neutron poison; S process; R matrix
• Public URL: https://hull-repository.worktribe.com/output/561946
• Publisher URL: https://aip.scitation.org/doi/10.1063/1.4768509