Influence of nuclear physics inputs and astrophysical conditions on the Th/U chronometer

The productions of thorium and uranium are key ingredients in r-process nucleo-cosmochronology. With the combination of improved nuclear and stellar data, we have made a detailed investigation of the r-process abundance pattern in the very metal-poor halo stars based on the classical r-process approach. It is found that the results are almost independent of specified simulations to observed abundances. The influence from nuclear mass uncertainties on a Th/U chronometer can approach 2 Gyr. Moreover, the ages of the metal-poor stars HE 1523-0901, CS 31082-001, and BD +17(degrees)3248 are determined as 11.8 +/- 3.7, 13.5 +/- 2.9, and 10.9 +/- 2.9 Gyr, respectively. The results can serve as an independent check for age estimates of the Universe.