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Validation of the Reaction Path of Rapid Proton Capture Process

The most common form of thermonuclear stellar explosion in the Galaxy is a type I X-Ray burst. The rapid proton capture process (rp-process), being the fundamental nucleosynthesis mechanism in X-Ray bursts, is always an important scientific frontier in nuclear astrophysics. Titanium-42 is a typical branching nucleus in the rp-process, hence the precision of the 42Ti (p, γ)43V reaction rate is critical for fully comprehending the rp-process reaction route in X-Ray bursts.

Validation of the Reaction Path of Rapid Proton Capture Process

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An international nuclear astrophysics team coordinated by Suqing Hou of the Institute of Modern Physics (IMP), Chinese Academy of Sciences (CAS), has determined the precise 42Ti(p,γ)43V reaction rates and validated the rp-process reaction route.

Astronomy & Astrophysics published the findings on September 18th, 2023.

The study also included researchers from 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).

Based on the whole resonance information and the most recent nuclear mass of vanadium-43, the researchers calculated the new 42Ti(p,γ)43V reaction rates. They discovered that the new rates differed by at least two orders of magnitude for forward rates and four orders of magnitude for reverse rates in the temperature range of X-Ray burst interest.

The rp-process nucleosynthesis calculations revealed that employing the revised forward and reverse rates might result in abundance fluctuations for scandium and calcium that were 128% and 49% higher, respectively, than using the statistical model rates. The general abundance pattern, on the other hand, remained unaffected.

Using the new rates, the researchers established that the 42Ti(p, γ)43V(p, γ)44Cr(β+)44V reaction path was a critical branch of the rp-process in X-Ray bursts.

Journal Reference:

Hou, S. Q., et al. (2023) Improved thermonuclear rate of 42Ti(p,γ)43V and its astrophysical implication in the rp process. Astronomy & Astrophysics. doi:10.1051/0004-6361/202347054


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