SIMBAD references

The d Scuti stars are pulsating variables useful for studies of stellar structure and evolution. Though new and improved models of stars and stellar physics have increased our understanding of these variables in recent years, some aspects of their behavior such as period changes are still poorly understood. Period changes may arise from a variety of evolutionary and non-evolutionary causes including undiscovered binarity, nonlinear mode-coupling, and secular changes in chemical structure. In this review, I will briefly summarize current observations and theories on period changes in d Scuti stars, and suggest ways that the AAVSO community can contribute to this important field.