  This paper provides estimates of convective turnover time scales for Sun-like
stars in the pre-main sequence and early post-main sequence phases of
evolution, based on up-to-date physical input for the stellar models. In this
first study, all models have solar abundances, which is typical of the stars in
the Galactic disk where most of the available data have been collected. A new
feature of these models is the inclusion of rotation in the evolutionary
sequences, thus making it possible to derive theoretically the Rossby number
for each star along its evolutionary track, based on its calculated rotation
rate and its local convective turnover time near the base of the convection
zone. Global turnover times are also calculated for the complete convection
zone. This information should make possible a new class of observational tests
of stellar theory which were previously impossible with semi-empirical models,
particularly in the study of stellar activity and in research related to
angular momentum transfer in stellar interiors during the course of stellar
evolution.
