THE BETA PICTORIS PROTOPLANETARY SYSTEM .12. PLANETARY PERTURBATIONS IN THE DISK AND STAR-GRAZING BODIES

The sporadic circumstellar spectroscopic variations detected since 1985 towards beta-Pic have been formerly interpreted as the result of the evaporation of small cometary-like bodies in the vicinity of the star. More recently, we proposed a model where these events could be due to planetary perturbations by an hypothetic planet in the disk. We develop here a complete study of perturbations of small bodies by a planet. The first result is that, in order to generate star-grazing orbits by perturbations, the planet's orbit has to be elliptical. The subsequent numerical statistical study shows that the model is fairly well suited to explain the observations. The major input parameters of the simulation can be estimated by a comparison between the simulation's results and the observational data. Moreover, the drastic temporal changes in the frequency of observed events, still unexplained, are reproduced and presented as a direct consequence of the model. Such a model, if confirmed, has probably important consequences on the history of beta-Pic's disk, which need now to be investigated.