UNCERTAINTIES IN THE νp-PROCESS: SUPERNOVA DYNAMICS VERSUS NUCLEAR PHYSICS

We examine how the uncertainties involved in supernova dynamics, as well as in nuclear data inputs, affect the ν p -process in the neutrino-driven winds. For the supernova dynamics, we find that the wind termination by the preceding dense ejecta shell, as well as the electron fraction ( Y e,3 ; at 3 × 10 9 K), plays a crucial role. A wind termination within the temperature range of (1.5–3) × 10 9 K greatly enhances the efficiency of the ν p -process. This implies that the early wind phase, when the innermost layer of the preceding supernova ejecta is still ∼200–1000 km from the center, is most relevant to the ν p -process. The outflows with Y e,3 = 0.52–0.60 result in the production of the p -nuclei up to A = 108 with interesting amounts. Furthermore, the p -nuclei up to A = 152 can be produced if Y e,3 = 0.65 is achieved. For the nuclear data inputs, we test the sensitivity to the rates relevant to the breakout from the p–p chain region ( A < 12), to the ( n , p ) rates on heavy nuclei, and to the nuclear masses along the ν p -process pathway. We find that a small variation of the rates of triple-α and of the ( n , p ) reaction on 56 Ni leads to a substantial change in the p -nuclei production. We also find that 96 Pd ( N = 50) on the ν p -process path plays a role as a second seed nucleus for the production of heavier p -nuclei. The uncertainty in the nuclear mass of 82 Zr can lead to a factor of two reduction in the abundance of the p -isotope 84 Sr.