The importance of nuclear masses in the astrophysical rp-process

The importance of mass measurements for astrophysical capture processes in general, and for the rp-process in X-ray bursts in particular is discussed. A review of the current uncertainties in the effective lifetimes of the major waiting points 64Ge, 68Se, and 72Kr demonstrates that despite of recent measurements uncertainties are still significant. It is found that mass measurements with an accuracy of the order of 10 keV or better are desirable, and that reaction rate uncertainties play a critical role as well.Comment: 14 pages, 4 figures, to appear in International Journal of Mass Spectroscop

The Influence of Reaction Rates on the Final p-Abundances

The astrophysical p-process is responsible for the origin of the proton rich nuclei,which are heavier than iron. A huge network involving thousands of reaction rates is necessary to calculate the final p-abundances. But not all rates included in the network have a strong influence on the p-nuclei abundances. The p-process was investigated using a full nuclear reaction network for a type II supernovae explosion when the shock front passes through the O/Ne layer. Calculations were done with a multi-layer model adopting the seed of a pre-explosion evolution of a 25 mass star. In extensive simulations we investigated the impact of single reaction rates on the final p-abundances. The results are important for the strategy of future experiments in this field.Comment: 4 page

Oxygen-Evolving Extracts from a Thermophilic Cyanobacterium Synechococcus sp.

Spheroplast membranes of a thermophilic cyanobacterium Synechococcus sp. have been treated with the detergent lauryldim ethylam ine oxide (LDAO). The resulting extracts show (1) light-induced O2 evolution with artificial electron acceptors, (2) four-fold enhancement of the O2 evolution relative to chlorophyll, (3) parallel increase of both the molar ratios of PS 2/C hl and cyt b559/Chl in the extract, (4) dissociation of the auxiliary pigment phycocyanin upon treatment with LDAO, but still tight association of allophycocyanin to the photosystem 2 preparation