Isotopic abundance of heavy elements and Galactic chemical evolution

Speaker: Yuta Yamazaki (U. of Tokyo, *Student talk)


The origin of heavy elements in the universe is one of the most important problem in this century. In this talk, I demonstrate how isotopic abundances are theoretically significant in studying the evolution of heavy elements. Astronomical observations indicate that galactic stars have similar elemental abundance patterns. Its ‘universality’ has been considered as a clue of the existence of one dominant r-process site as r-process is the only powerful primary process and influential since the early galaxy. However, recent calculations suggest that different r-process astrophysical sites, such as supernovae or neutron star mergers, can produce similar ELEMENTAL abundance patterns while their ISOTOPIC abundance patterns differ. We performed galactic chemical evolution (GCE) simulations considering multiple r-process sites and reveal how the r-process isotopic abundance pattern has changed while keeping the similar elemental abundance pattern. I will also present very recent results of the evolution of p-nuclides. Dominant nucleosyntheses including r-process are neutron capture processes which can not produce proton rich isotopes. Thus, other processes are required to explain the existence of such nuclides. Recent studies suggest that vp process is a possible solution. We performed GCE calculation for some p-isotopes and show their effects on the evolution of observable elemental abundances.