Time Dependence of Observables for a Cepheid Variable Star

This animation illustrates the variation in time of the radius, surface temperature, spectral class, and luminosity of a Cepheid variable (in fact, the example is delta Cephei itself). We show a simple change in size for the pulsation, but internally the pulsation is more complex than a simple overall change in size. Usage: Use the "Play" button and "Stop" button to control play. You may find it particularly useful to use the "Step" and "Back" buttons to step through the pulsation cycle. "Home" returns to the beginning from any point.