Winzer (1974) discovered that the A0p Si star HR 7224 (Cowley et al. 1969) was a light variable with a period of 1.1663 days when he obtained UBV photometry. He used 55 Dra as a comparison star. The largest amplitude was 0.05 mag in U.
One hundred fifty-four FCAPT uvby observations were
made during years 4 and 5. The periodogram analysis showed
that Winzer's period was approximately correct. His V
magnitudes were used with the FCAPT y values to adjust the
period. The follow ephemeris was adopted
Figure 3 (click here) shows the FCAPT observations (plus signs) and the V values of Winzer (closed squares) transformed to y of HR 7224 plotted according to this ephemeris. The star exhibits in-phase variations in all four magnitudes with two nearly equal minima, which are about 0.4 of the period apart, separated by a sub-maximum as well as a well-defined maximum. The minimum occurring earlier in phase is always slightly less deep than the second minimum. The amplitudes are 0.06 mag in u, 0.045 mag in v, 0.035 mag in b, and 0.03 mag in y.