Electron capture plays a pivotal role in the complex dynamics of supernova explosion.The electron capture rates on 55Co have been calculated by means of the proton-neutron quasiparticle random phase approximation (pn-...Electron capture plays a pivotal role in the complex dynamics of supernova explosion.The electron capture rates on 55Co have been calculated by means of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. We have calculated these stellar electron capture rates for temperatures (in 109 K) 0. 01, 0. 1, 0. 2, 0.4, 0. 7, 1, 1.5, 2, 3, 5, 10, 30 and densities between 10 g · cm-3 and 1011 g · cm-3. Here we report the differences in electron capture rates with the rates of large shell model calculations.展开更多
The ^(12)C+^(12)C reaction rate plays an essential role in stellar evolution and nucleosynthesis.Nevertheless,the uncertainties of this reaction rate are still large.We calculate a series of stellar evolution models w...The ^(12)C+^(12)C reaction rate plays an essential role in stellar evolution and nucleosynthesis.Nevertheless,the uncertainties of this reaction rate are still large.We calculate a series of stellar evolution models with the near solar abundance from the zero-age main-sequence through presupernova stages for initial masses of 20 M_(⊙) to 40 M_(⊙).The ^(12)C+^(12)C reaction rates from two different studies are used in our investigation.One is the rate obtained using the Trojan Horse Method(THM)by Tumino et al.[Nature 557(7707),687(2018)],and the other was obtained by Mukhamedzhanov et al.[Physical Review C 99(6),064618(2019)](Muk19).Then,comparisons of the nucleosynthesis and presupernova isotopic abundances are conducted.In particular,we find that in the C burning shell,models with the THM produce a smaller amount of ^(23)Na and some neutron-rich isotopes than Muk19.The difference in the abundance ratios of Na/Mg,S/Mg,Ar/Mg,and K/Mg between the two models are apparent.We compare Na/Mg obtained from our theoretical presupernovae models with Na/Mg in stellar atmospheres observed with high-resolution spectra as well as from the latest galactic chemical evolution model.Although Na/Mg obtained using the THM is within 2σ of the observed stellar ratio,the theoretical uncertainty on Na/Mg introduced by the uncertainty of the ^(12)C+^(12)C reaction rate is almost equivalent to the standard deviation of astronomical observations.Therefore,a more accurate ^(12)C+^(12)C reaction rate is crucial.展开更多
文摘Electron capture plays a pivotal role in the complex dynamics of supernova explosion.The electron capture rates on 55Co have been calculated by means of the proton-neutron quasiparticle random phase approximation (pn-QRPA) theory. We have calculated these stellar electron capture rates for temperatures (in 109 K) 0. 01, 0. 1, 0. 2, 0.4, 0. 7, 1, 1.5, 2, 3, 5, 10, 30 and densities between 10 g · cm-3 and 1011 g · cm-3. Here we report the differences in electron capture rates with the rates of large shell model calculations.
基金Supported by the National Natural Science Foundation of China(11988101,11890694)the National Key R&D Program of China(2019YFA0405502)K.Nomoto is supported by the World Premier International Research Center Initiative(WPI),MEXT,Japan,and the Japan Society for the Promotion of Science(JSPS)KAKENHIgrant(JP17K05382,JP20K04024,JP21H04499)。
文摘The ^(12)C+^(12)C reaction rate plays an essential role in stellar evolution and nucleosynthesis.Nevertheless,the uncertainties of this reaction rate are still large.We calculate a series of stellar evolution models with the near solar abundance from the zero-age main-sequence through presupernova stages for initial masses of 20 M_(⊙) to 40 M_(⊙).The ^(12)C+^(12)C reaction rates from two different studies are used in our investigation.One is the rate obtained using the Trojan Horse Method(THM)by Tumino et al.[Nature 557(7707),687(2018)],and the other was obtained by Mukhamedzhanov et al.[Physical Review C 99(6),064618(2019)](Muk19).Then,comparisons of the nucleosynthesis and presupernova isotopic abundances are conducted.In particular,we find that in the C burning shell,models with the THM produce a smaller amount of ^(23)Na and some neutron-rich isotopes than Muk19.The difference in the abundance ratios of Na/Mg,S/Mg,Ar/Mg,and K/Mg between the two models are apparent.We compare Na/Mg obtained from our theoretical presupernovae models with Na/Mg in stellar atmospheres observed with high-resolution spectra as well as from the latest galactic chemical evolution model.Although Na/Mg obtained using the THM is within 2σ of the observed stellar ratio,the theoretical uncertainty on Na/Mg introduced by the uncertainty of the ^(12)C+^(12)C reaction rate is almost equivalent to the standard deviation of astronomical observations.Therefore,a more accurate ^(12)C+^(12)C reaction rate is crucial.
