β Pictoris: evidence of light variations.

We have analyzed β Pictoris photometric measurements obtained from La Silla by the Geneva Observatory from 1975 to 1992. These data show evidence of variations in the brightness of the star, with no color dependency. Here, we demonstrate that the light variations are present on long as well as on short time scales. On a long time scale, we show that the apparent magnitude of β Pictoris decreased by 0.011+/-0.004mag from 1979 to 1982. Moreover, when we consider all the measurements, the chance that there is no variation at all can be estimated to be less than 10^-4^. On short time scales there is a peculiar feature observed during about 30 days; the variations may be as high as 0.04mag magnitude. A maximum entropy reconstruction of the photometric data is tentatively proposed and some physical interpretations are presented.