  The solar magnetic activity cycle is responsible for periodic episodes of
severe space weather, which can perturb satellite orbits, interfere with
communications systems, and bring down power grids. Much progress has recently
been made in forecasting the strength and timing of this 11-year cycle, using a
predictive flux-transport dynamo model (Dikpati 2005, Dikpati et al. 2006). We
can strengthen the foundation of this model by extending it to match
observations of similar magnetic activity cycles in other Sun-like stars, which
exhibit variations in their Ca II H and K emission on time scales from 2.5 to
25 years (Baliunas et al. 1995). This broad range of cycle periods is thought
to reflect differences in the rotational properties and the depth of the
surface convection zone for stars with various masses and ages.
Asteroseismology is now yielding direct measurements of these quantities for
individual stars, but the most promising asteroseismic targets are in the
southern sky (alpha Cen A, alpha Cen B, beta Hyi), while the existing activity
cycle survey is confined to the north. We are initiating a long-term survey of
Ca II H and K emission for a sample of 92 southern Sun-like stars to measure
their magnetic activity cycles and rotational properties, which will ultimately
provide independent tests of solar dynamo models.
