Assistant to the Director,
AASVO, Cambridge, Massachusetts
Abstract
RV Tauri stars are yellow
supergiant variables with light curves that have alternating deep and shallow
minima. The amplitudes of light variations are on the order of 1.5 to 2.5
magnitudes, with occasional rises that exceed these limits. The periods,
defined as the interval between two deep minima are 50 to 100 days. Many show
long period changes of 500 to 9000 days in their mean magnitudes (Kameny,
1956). The light curves do not repeat at each cycle. Occasionally there may be
irregularities in the light curve, or absence of the scheduled minima, or an
exchange of deep and shallow minima. It has been noticed that the maximum
following a deep minimum is usually brighter than the preceding few maxima.