874 research outputs found

    From the microcosm of the atomic nuclei to the macrocosm of the stars

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    A necessary condition for the reliable modelling of the structure or evolution of the stars and of their concomitant nucleosynthesis is the availability of good quality nuclear data in a very wide area of the chart of nuclides. This short review presents a non-exhaustive list of nuclear data of astrophysics interest (masses, β\beta-decays, thermonuclear and non-thermonuclear reaction rates) for nuclides at the bottom of the valley of nuclear stability (mainly involved in the modelling of non-explosive phases of stellar evolution), or for more or less highly exotic nuclides (to be considered in the description of stellar explosions). Special emphasis is put on the importance of providing quality nuclear data bases that can be easily used by astrophysicists.Comment: 6 pages, To appear in Proceedings of International Conference on Nuclear Data for Science and Technology 2007 (ND2007), Nice, Franc

    Theoretical photo-disintegration of 16^{16}O

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    The photodisintegration of 16^{16}O is predicted to be dominated by EE2 excitation in the vicinity of the α\alpha-particle threshold. The reaction rates of 12^{12}C(α\alpha,γ\gamma)16^{16}O are expected to be determined from this reaction.Comment: 3 pages, 2 figures, Proceedings of Nuclei in the Cosmos (NIC-XIV). 19-24 June 2016, Niigata, Japa

    What Is Required to Ensure the Human Security of Refugees?

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    Direct triple-α\alpha process in non-adiabatic approach

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    Triple-α\alpha reaction rates have been determined well with the sequential process via the narrow resonances. However, the direct triple-α\alpha process at off-resonant energies still remains in unsolved problems. In the present report, the direct triple-α\alpha contribution is estimated with a non-adiabatic method, and it is found to be 1015^{-15}--103^{-3} pb order in photodisintegration cross sections of 12^{12}C(21+^+_1 \rightarrow 0+^+) for 0.15<E<0.350.15 < E < 0.35 MeV. This is far below the values predicted by the recent adiabatic models. In spite of the large difference, the derived rates are found to be concordant with NACRE at the helium burning temperatures.Comment: 4 pages, 2 figures; Proceedings of 16th International Symposium on Origin of Matter and Evolution of Galaxies (OMEG16), 25-28 October 2022, Hanoi, Vietna
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