The Regulated GeAs Cycles with the New 63 Ga(p, γ ) 64 Ge and 64 Ge(p, γ ) 65 As Reaction Rates and Their Impact on the GS 1826−24 Clocked Bursts and SAX J1808.4−3658 Photospheric Radius Expansion Bursts
Year: 2025
Type: article
Abstract: The 63 Ga(p, γ ) 64 Ge and 64 Ge(p, γ ) 65 As thermonuclear reactions connect the ZnGa and GeAs cycles by diverting the flow of the rapid proton-capture process from 63 Ga to 65 As. Changes in these two reaction rates regulate the ZnGa and GeAs cycles and may affect the modeled properties matching with the observed counterparts of a type I X-ray burster. We implement the latest 63 Ga(p, γ ) 64 Ge and 64 Ge(p, γ ) 65 As reaction rates to the state-of-the-art self-consistent one-dimensional multizone thermohydrodynamic code K epler to study the influence of these new reaction rates on the models of the GS 1826−24 clocked burster and SAX J1808.4−3658 photospheric radius expansion burster. Both new reaction rates obtained by Lu et al. are determined from complementing the experimental input with the nuclear spectroscopic information deduced from the full pf -shell space configuration interaction shell model calculations. By constraining the models on reproducing the observed burst peak, light-curve profile, fluence, and recurrence time, we find that the impact of the newly measured proton thresholds and respective proton-capture reactions on the burst light-curve profile of the GS 1826−24 clocked burster is, in fact, not as significant as claimed by Zhou et al. With or without the inclusion of the newly determined reaction rate of the highly influential 22 Mg( α , p) 25 Al reaction, the impact of the new 63 Ga(p, γ ) 64 Ge and 64 Ge(p, γ ) 65 As reaction rates on SAX J1808.4−3658 photospheric radius expansion bursts is evident. Our finding indicates that the models reproducing the 2002 October epoch of the SAX J1808.4−3658 photospheric radius expansion burster are more sensitive to the uncertainties of thermonuclear reaction rates.
Source: The Astrophysical Journal
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Funders: National Science Foundation, Strong, Joint Institute for Nuclear Astrophysics - Center for the Evolution of the Elements, Advanced Storage Research Consortium, Ministry of Education, Culture, Sports, Science and Technology, Monash University, National Natural Science Foundation of China, Academia Sinica, Chinese Academy of Sciences, Ministry of Science and Technology of the People's Republic of China, National Astronomical Observatory of Japan, Zhejiang Sci-Tech University, Yukawa Institute for Theoretical Physics, Kyoto University, Japan Society for the Promotion of Science, Japan Atomic Energy Agency, RIKEN, National Key Research and Development Program of China, Oak Ridge National Laboratory
Awards: JINA Center for the Evolution of the Elements, Solution for the neutrino mass hierarchy problem by revealing the process of nucleosynthesis in supernova, G201294217, G2243207195, G2389541491, G2399045919, G2461013610, G267863865, G2695431083, G3714824817, G4653965180, G4832076570, G4974873094, Study of reaction rate of the rapid neutron capture process in supernovae and neutron star merger, Confirmation of the linear cluster chain state in atomic nucleus, G5985245239, G7111999867, G7316479717, G7322807242, I型X射线暴中的关键质子俘获过程和beta衰变研究, G8228441524, G8570682797, G8711473250, G9000377301, G909400086
OpenAlex ID: W4415622659