  The purpose of this work is to resume investigation of Galactic thin disk
dating using nucleocosmochronology with Th/Eu stellar abundance ratios, a theme
absent from the literature since 1990. [Th/Eu] abundance ratios for a sample of
20 disk dwarfs/subgiants of F5 to G8 spectral type with -0.8 <= [Fe/H] <= +0.3,
determined in the first paper of this series, were adopted for this analysis.
We developed a Galactic chemical evolution model that includes the effect of
refuses, which are composed of stellar remnants (white dwarfs, neutron stars
and black holes) and low-mass stellar formation residues (terrestrial planets,
comets, etc.), contributing to a better fit to observational constraints. Two
Galactic disk ages were estimated, by comparing literature data on Th/Eu
production and solar abundance ratios to the model ((8.7 +5.8-4.1) Gyr), and by
comparing [Th/Eu] vs. [Fe/H] curves from the model to our stellar abundance
ratio data ((8.2 +/- 1.9) Gyr), yielding the final, average value (8.3 +/- 1.8)
Gyr. This is the first Galactic disk age determined via Th/Eu
nucleocosmochronology, and corroborates the most recent white dwarf ages
determined via cooling sequence calculations, which indicate a low age (<~ 10
Gyr) for the disk.
