Nucleo-cosmochronology and chemical evolution modellings

In an attempt to place nucleo-cosmochronology in perspective, we revisit the Re-187-Os-187 chronometry with the use of a schematic two-zone model of chemical evolution in the solar neighbourhood and present some exemplifying results. We then elucidate the meaning of such chronometric studies, which rely on the isotopic abundances in the solar system, in relation to those spirited by the recent observations of Th and U abundances in the surfaces of very metal-poor stars. We argue that further pursuit of 'nuclear clocks' would certainly unfold some important features of stellar nucleosynthesis processes and the galactic chemical evolution, whereas the very quest for an unambiguous derivation of the age of the nuclear species in our galaxy would likely remain unrequited for some time to come.