出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：We report the detailed abundance patterns of neutron-capture elements in four very metal-poor
stars. The abundance patterns of heavy neutron-capture elements in the two objects HD 6268 and
HD 115444 are quite similar to that of the r-process component in the Solar-System, while their
abundances of light neutron-capture elements show deviation from that. The actinide element
thorium is detected in these objects. These stars well represent the abundance pattern produced
by the so-called main r-process. The other two stars, HD 88609 and HD 122563, have quite low
abundances of heavy neutron-capture elements. However, the light neutron-capture elements in
these stars show large excesses with respect to heavy ones, indicating a contribution of another
process than the main r-process. These results provide useful for investigations of the neutroncapture
nucleosynthesis in the early universe.
