HIP 7666 is a variable star newly discovered during the Hipparcos mission and classified as of unknown type (ESA 1997). During 23 nights between July 2000 and November 2000, over 2300 CCD observations in the V band were obtained. These data show that the new variable is a detached eclipsing binary system with an orbital period of 2.37229 days. In addition, one of the components undergoes very s...

Amplitude and phase variability are commonly found in many different types of pulsating stars. This suggests a common, presently unknown physical origin. We have examined the phenomenon in several δ Scuti stars with extensive data and find the beating of close frequencies to be responsible. This is demonstrated for the star FG Vir by testing the relationship between the observed amplitude and p...