Short-lived p-nuclides in the early solar system and implications on the nucleosynthetic role of X-ray binaries

Abstract

The data available for short-lived $p$-nuclides are used in an open nonlinear model of the chemical evolution of the Galaxy in order to discuss the origin of extinct radionuclides, the stellar sources of $p$-nuclides, and the chronology of solar system formation. It is concluded that the observed abundances of ${}^{97}$Tc, ${}^{98}$Tc, ${}^{92}$Nb, and ${}^{146}$Sm in the early solar system are consistent with nucleosynthesis in type II supernovae during continuous chemical evolution of the Galaxy and a subsequent short isolation of the presolar molecular cloud from fresh nucleosynthetic inputs. However, further work on supernova models is needed before $p$-radionuclides will comprise reliable cosmochronometers. Despite these limitations, we argue that niobium-92 can be used to test whether the {\it rp}-process contributed to the synthesis of light {\it p}-nuclides in the Mo-Ru region.

8 pages, 2 figures. Proceedings of the Nuclear Physics in Astrophysics Conference, Debrecen, Hungary, 2002, to appear in Nucl. Phys. A