Nuclear cosmochronometry and universality in the r-process abundances

We study r-process nucleosynthesis in various environments to clarify recent controversial observations. We find that the observed universality of the r-process can be reproduced in a large variety of nucleosynthesis environments. On the other hand, the Eu to actinide production ratio strongly depends upon the nucleosynthesis environment. Our study implies that the Th/Eu chronometer is very uncertain, while the U/Th chronometer is robust.