On the variability of the A0 supergiants 9 Per, HR 1035, 13 Mon, Deneb, and HR 8020 as seen in FCAPT Strömgren photometry
We present differential Strömgren uvby Four College Automated Photometric Telescope (FCAPT) observations of five supergiants with spectral types near A0. For three stars we supplemented our new data with our earlier published data, and for two more stars we present new data. We used two computer programs Period04 and VStar in attempts to determine if significant periodicities are present. Some periods we found may not be real as their yearly coverages are only less about four months. Five years of 9 Per photometry and 11 years of HR 8020 photometry both suggest a period of 248 days which is 2/3 of a year. 13 Mon and HR 1035 may be variable, but the data we have taken does not permit us to determine their periods. Our most complete datasets for Deneb and for HR 8020 indicate very complex variability. This is not unexpected for stars with atmospheres where convection is the dominant mode of energy transportation. Among our five supergiants, 13 Mon has the smallest amplitudes for u, v, b, and y. Better sets of photometry for these stars require observing seasons to be as long as possible and should cover many observations per night rather than one. This should remove any effects of data being undersampled.