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13 10, 2023
Scientists Confirm a Reaction Path of Rapid Proton Capture Process
Type I X-ray bursts are the most frequent types of thermonuclear stellar explosions in the Galaxy. As the key nucleosynthesis process in X-ray bursts, the rapid proton capture process (rp-process) is always the important scientific frontier in nuclear astrophysics. Titanium-42 is a typical branching nucleus in the rp-process, so the accuracy of 42Ti(p, γ)43V reaction rate is crucial for comprehensively understanding the reaction path of rp-process in X-ray bursts.
Recently, an international nuclear astrophysical team led by HOU Suqing from the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), has successfully derived the accurate 42Ti(p, γ)43V reaction rates and confirmed a reaction path of the rp-process. The results were published in Astronomy & Astrophysics.
Other institutions involved in the study include the University of North Carolina(US), Duke University (US), the Hungarian Academy of Sciences (Hungary), the University of Hull (UK) and the Joint Institute for Nuclear Astrophysics (US).
The researchers obtained the new 42Ti(p, γ)43V reaction rates based on the complete resonance information and the latest nuclear mass of vanadium-43. They find that the new rates are different from previous rates from the statistical model by at least 2 orders of magnitude for forward rate and 4 orders of magnitude for reverse rate in the temperature range of X-ray burst interest.
The rp-process nucleosynthesis calculations show that the adoption of the new forward and reverse rates can result in abundance variations for scandium and calcium by 128% and 49%, respectively, compared with the variations using the statistical model rates. On the other hand, the overall abundance pattern is not significantly affected.
By using new rates, the researchers confirm that the reaction path of 42Ti(p, γ)43V(p, γ)44Cr(β+)44V is a key branch of the rp-process in X-ray bursts.
This work was supported by the National Key R&D Program of China, the Strategic Priority Research Program of CAS and the Youth Innovation Promotion Association of CAS.
Fig 1. Decayed elemental abundance distribution in the rp-process for cases with different forward and reverse reaction rates for 42Ti(p, γ)43V. (Image by HOU Suqing)
Fig 2. Main reaction flows in the rp-process for the adoption of different forward and reverse reaction rates for 42Ti(p, γ)43V. (Image by HOU Suqing)
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Contact Information
Institute of Modern Physics
Email: fangliu@impcas.ac.cn
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