The gaseous component of the debris disk surrounding Beta Pictoris has been subject of 
detailed observations. The characteristics of the CO detected with HST and the search 
for H2 with FUSE demonstrated that the evaporation of frozen bodies like comets must 
produce the CO seen in the disk. Extensive observations of spectral variability of Beta 
Pictoris are now interpreted by extrasolar comets evaporating in the vicinity of the 
central star in this young planetary system. We will present the result of a large 
survey of these extrasolar comets carried out with HARPS. For the first time, these 
observations allowed us to discriminate two different dynamical families of comets. One 
family could be the result of a recent break-up of one or two comets, while the dynamical 
characteristics of the other family is consistent with a mean motion resonance with a 
massive planet as proposed by Beust & Morbidelli. In short, we are witnessing an intense 
cometary activity which is likely similar to the one which took place four billion years 
ago in our own Solar system.