1996A&A...310..181B

Variable redshifted absorption features in the spectrum of βPictoris have been attributed to comet-like bodies falling towards the star. Recent observations showed that some of the detected absorption features last much longer than predicted by the suggested scenario for one single body. Here, we invoke the successive infall of several bodies to explain these observations. We develop a statistical model of comet arrival, based on a Poissonian process, and show that the long duration of spectral features is highly probable if the arrival rate of bodies is high enough. Dynamical simulations involving several evaporating bodies are presented, showing that multi-component structures very similar to those observed are easily reproduced, reinforcing thus the scenario. We discuss the implications of the constraints deduced from this study on the possible generation mechanism for such an infall of bodies towards the star and we show that a simple model based on the disruption of one single larger body is not compatible with the observational constraints.