Long-term photometry of Be stars. II. Periodic variations on time scales of days to months.

Stroemgren differential uvby photometry of 4 Be stars is analysed. The data were taken during the time interval 1983-1994 in the framework of the Long-Term Photometry of Variables project at La Silla. We detected in these four stars periodic photometric variations with periods between 4 and 93 days. The two cases with the longest periods (FT CMa with P=87.9d and FY CMa with P=92.7d) did not have any previously known periodic variability. In three of the four cases the periodic oscillation was coherent and always present during the 10 years of monitoring.