H. Herndl

The reaction rate for 31S(p,γ)32Cl and its influence on the SiP‐cycle in hot stellar hydrogen burning

The 31S(p,u2009γ)32Cl reaction rate has been measured for 3He energies between 22.5 and 25 MeV at forward angles. Excitation energies and spin‐parities of the observed levels in 32Cl are derived. These data are used to calculate flow patterns of nuclear reactions in the mass range A=22–26 for temperatures and densities of astrophysical interest. (AIP)

Thermonuclear reaction rate of 23mg(p,gamma)24al

Updated stellar rates for the reaction 23Mg(p,gamma)24Al are calculated by using all available experimental information on 24Al excitation energies. Proton and gamma-ray partial widths for astrophysically important resonances are derived from shell model calculations. Correspondences of experimentally observed 24Al levels with shell model states are based on application of the isobaric multiplet mass equation. Our new rates suggest that the 23Mg(p,gamma)24Al reaction influences the nucleosynthesis in the mass A>20 region during thermonuclear runaways on massive white dwarfs.

Thermonuclear reaction rate of {sup 23}Mg(p,{gamma}){sup 24}Al

Updated stellar rates for the reaction 23Mg(p,gamma)24Al are calculated by using all available experimental information on 24Al excitation energies. Proton and gamma-ray partial widths for astrophysically important resonances are derived from shell model calculations. Correspondences of experimentally observed 24Al levels with shell model states are based on application of the isobaric multiplet mass equation. Our new rates suggest that the 23Mg(p,gamma)24Al reaction influences the nucleosynthesis in the mass A>20 region during thermonuclear runaways on massive white dwarfs.

Thermonuclear reaction rate of23Mg(p,γ)24Al

Updated stellar rates for the reaction 23Mg(p,gamma)24Al are calculated by using all available experimental information on 24Al excitation energies. Proton and gamma-ray partial widths for astrophysically important resonances are derived from shell model calculations. Correspondences of experimentally observed 24Al levels with shell model states are based on application of the isobaric multiplet mass equation. Our new rates suggest that the 23Mg(p,gamma)24Al reaction influences the nucleosynthesis in the mass A>20 region during thermonuclear runaways on massive white dwarfs.

Measurement of the neutron capture cross sections of 15N and 18O

Preliminary experimental results are presented for neutron capture cross sections of 15N and 18O for neutron energies of 25, 152, 250, and 371 keV. The cross sections were used to calculate the capture reaction rates at stellar temperatures, around 0.1–1.0 GK. (AIP)

Sequential proton capture reactions in the rp-process

Detailed shell shell model calculations have been performed to study the structure of unbound excited states in the neutron deficient T=3/2 and T=2 nuclei in the mass range A=20–30. Excitation energies, single particle structure as well as γ transition strengths were computed. On the basis of these results new reaction rates were calculated for the two proton capture sequences, 22Mg(p,γ)23Al(p,γ)24Si and 26Si(p,γ)27P(p,γ)28S. The consequences of these new rates for the reaction flow and the rp‐process nucleosynthesis at different stellar temperature and density conditions will be discussed.