BETA-PICTORIS - EVIDENCE OF LIGHT VARIATIONS

We have analyzed beta 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 de pendency. Here, we demonstrate that the light variations are present o n long as well as on short time scales. On a long time scale, we show that the apparent magnitude of beta Pictoris decreased by 0(m).011 +/- 0(m).004 from 1979 to 1982. Moreover, when we consider all the measur ements, 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 featu re observed during about 30 days; the variations may be as high as 0(m ).04 magnitude. A maximum entropy reconstruction of the photometric da ta is tentatively proposed and some physical interpretations are prese nted.