  We present a detailed study of the small frequency separations as diagnostics
of the mass of the convective core and evolutionary stage of solar-type stars.
We demonstrate how the small separations can be combined to provide sensitive
tests for the presence of convective overshoot at the edge of the core. These
studies are focused on low degree oscillation modes, the only modes expected to
be detected in distant stars. Using simulated data with realistic errors, we
find that the mass of the convective core can be estimated to within 5% if the
total stellar mass is known. Systematic errors arising due to uncertainty in
the mass could be up to 20%. The evolutionary stage of the star, determined in
terms of the central hydrogen abundance using our proposed technique, however,
is much less sensitive to the mass estimate.
