On the Need for Deep-Mixing in Asymptotic Giant Branch Stars of Low Mass

A proposed direct measurement of cross section at Gamow window for key reaction 19F(p,α) 16O in Asymptotic Giant Branch stars with a planned accelerator in CJPL

“…The Gamow window is only partially covered by the unpublished data of Lorentz-Wirzba [29], which were utilized [30,31] later to evaluate the astrophysical factor in the zero and finite-range Distorted Wave Born Approximation (DWBA) approaches. These data support a strong suppression of compound 20 Ne decay to the ground state of 16 O at E cm ∼0.14-0.6 MeV. However, these results were not included in the NACRE compilation as possible systematic errors affecting the absolute normalization might lead * Refer to five proposals submitted to NSFC in 2014, W.P.…”

“…Here, the 19 F(p,α) 16 O reaction might bear a great importance as it would remove both protons and fluorine nuclei from the nucleosynthesis scenario. Therefore, the 19 F(p,α) 16 …”

“…However, these results were not included in the NACRE compilation as possible systematic errors affecting the absolute normalization might lead * Refer to five proposals submitted to NSFC in 2014, W.P. Liu et al, The 12 C(α,γ) 16 to an underestimate of S (E) by a factor of two [28]. The astrophysical factor was then extrapolated to low energies assuming a dominant contribution of the non-resonant part [28].…”

“…In order to solve the observed fluorine overabundances in Asymptotic Giant Branch (AGB) stars, measuring the key 19 F(p,α) 16 O reaction at effective burning energies (i.e., at Gamow window) is established as one of the scientific research sub-projects. The present paper describes this sub-project in details, including motivation, status, experimental setup, yield and background estimation, aboveground test, as well as other relevant reactions.…”

Stellar MHD and Nuclear Physics Coupled Together Solve the Puzzle of Oxide Grain Composition

“…Nowadays thanks to updates in CBP models ( [4], [5] and [6]) and high-precision measurements of nuclear reaction cross sections, the whole range of 17 15 O reaction rate by [7] and the 16 O(p,γ) 17 F one by [8] remarked that group 1 grains condensate in the envelope of RGB star of solar composition and with mass ≤ 2M ⊙ [6]. While proton capture cross sections on 17 O and 18 O measured by [9] and [10] decisively contribute to state that AGB stars with mass smaller than 1.5M ⊙ are reliable progenitors for group 2 grains [11].…”