The thermonuclear^19F（p,α0）16O reaction rate in the temperature region 0.007–10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolation...The thermonuclear^19F（p,α0）16O reaction rate in the temperature region 0.007–10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations.Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature（e.g. 0.01 GK） our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ^1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data（Isoya et al., Nucl. Phys.7, 116（1958）） in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK,and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data.Asymptotic giant branch（AGB） stars evolve at temperatures below 0.2 GK, where the^19F（p,α）16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section（or S factor） data in the low energy region are therefore needed for astrophysical nucleosynthesis studies.展开更多
基金Supported by National Natural Science Foundation of China(11490562,11490560,11675229)National Key Research and Development Program of China(2016YFA0400503)
文摘The thermonuclear^19F（p,α0）16O reaction rate in the temperature region 0.007–10 GK has been derived by re-evaluating the available experimental data, together with the low-energy theoretical R-matrix extrapolations.Our new rate deviates by up to about 30% compared to the previous results, although all rates are consistent within the uncertainties. At very low temperature（e.g. 0.01 GK） our reaction rate is about 20% lower than the most recently published rate, because of a difference in the low energy extrapolated S-factor and a more accurate estimate of the reduced mass used in the calculation of the reaction rate. At temperatures above ^1 GK, our rate is lower, for instance, by about 20% around 1.75 GK, because we have re-evaluated the previous data（Isoya et al., Nucl. Phys.7, 116（1958）） in a meticulous way. The present interpretation is supported by the direct experimental data. The uncertainties of the present evaluated rate are estimated to be about 20% in the temperature region below 0.2 GK,and are mainly caused by the lack of low-energy experimental data and the large uncertainties in the existing data.Asymptotic giant branch（AGB） stars evolve at temperatures below 0.2 GK, where the^19F（p,α）16O reaction may play a very important role. However, the current accuracy of the reaction rate is insufficient to help to describe, in a careful way, the fluorine over-abundances observed in AGB stars. Precise cross section（or S factor） data in the low energy region are therefore needed for astrophysical nucleosynthesis studies.
