RV Tau-type variables are pulsating supergiants, which form a rare class of objects in
the grand zoo of oscillating stars. The rarity is caused by the fact that these variables are
rapidly evolving post-Asymptotic Giant Branch stars, in which large amplitude radial pulsations
occur when evolving through the classical instability strip. In this talk first we discuss the impact
of the Kepler space telescope in the field via detailed analysis of DF Cygni, the single
RV Tau-type object in the original Kepler field. Then we turn our attention to the
so-called RVb phenomenon, the long-term modulation of the mean brightness in a
large fraction of the known RV Tau-type stars. We demonstrate an intriguing correlation between
the pulsation amplitude and mean brightness, when everything measured in fluxes, one that
can be naturally explained by time-dependent dust obscuration of a circumbinary disk.
Our results deliver a clear warning about the dangers of sticking to the traditional
magnitude system in the classical variable star investigations.
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