New constraints on the Al 25 (p,γ) reaction and its influence on the flux of cosmic γ rays from classical nova explosions

The astrophysical Al25(p,γ)Si26 reaction represents one of the key remaining uncertainties in accurately modeling the abundance of radiogenic Al26 ejected from classical novae. Specifically, the strengths of key proton-unbound resonances in Si26, that govern the rate of the Al25(p,γ) reaction under...

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Detalles Bibliográficos
Autores: Canete, L., Lotay, G., Christian, G., Doherty, D.T., Catford, W.N., Hallam, S., Seweryniak, D., Albers, H. M., Almaraz-Calderón, S., Bennett, E. Andrew, Carpenter, M. P., Chiara, C. J., Greene, J. P., Hoffman, C. R., Janssens, R. V. F., Kankainen, A., Lauritsen, T., Matta, A., Moukaddam, M.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2021
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/261000
Acceso en línea:http://hdl.handle.net/10261/261000
Access Level:acceso abierto
Palabra clave:Lifetimes and widths
Nuclear astrophysics
Nuclear reactions
Nuclear structure and decays
Nucleon induced nuclear reactions
Nucleosynthesis in explosive environments
Radiative capture
Descripción
Sumario:The astrophysical Al25(p,γ)Si26 reaction represents one of the key remaining uncertainties in accurately modeling the abundance of radiogenic Al26 ejected from classical novae. Specifically, the strengths of key proton-unbound resonances in Si26, that govern the rate of the Al25(p,γ) reaction under explosive astrophysical conditions, remain unsettled. Here, we present a detailed spectroscopy study of the Si26 mirror nucleus Mg26. We have measured the lifetime of the 3+, 6.125-MeV state in Mg26 to be 19(3)fs and provide compelling evidence for the existence of a 1- state in the T=1,A=26 system, indicating a previously unaccounted for=1 resonance in the Al25(p,γ) reaction. Using the presently measured lifetime, together with the assumption that the likely 1- state corresponds to a resonance in the Al25+p system at 435.7(53) keV, we find considerable differences in the Al25(p,γ) reaction rate compared to previous works. Based on current nova models, we estimate that classical novae may be responsible for up to ≈15% of the observed galactic abundance of Al26.

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