A Search for Low-amplitude Periodic Brightness Variations in HD 168 443

The paper presents the results of studying light curves of the star HD 168443 obtained from the ground-based and space photometric observations within the ASAS, KWS surveys, and the Hipparcos mission from 1990 to 2020. During 30 years of observations, the average annual brightness of the star remained constant within the measurement errors, the mean V-value was 6^m.96. Using the dense data series in 2007–2009, the photometric period of 34.7 days was found, and the low-amplitude brightness variability was studied with this period. We determined epochs and amplitude of rotational modulation produced by the development of active regions. These parameters do not change during 2–5 rotations of the star. The amplitude of the rotational modulation increases in 2007 before the epoch of maximum brightness. The star was the brightest in 2009, its V-magnitude was 6^m.92. The location of starspots on the surface of the star during these epochs is also considered.