On the Nature of Impacts Causing Cometary Outbursts

The study is focused on the nature of impacts causing cometary outbursts. Specifically, we analyze an issue on whether comets may pass through known swarms of meteoroids. We consider 116 comets, which exhibit outbursts, from the list of Andrienko and Vashchenko (1981) and 102 meteor streams, the orbital elements of which are reliably known. The epochs of outbursts and passages of comets in the vicinity of meteoroid swarms are compared. For 24 comets these epochs differ only by ten days, if the swarms' zones are assumed to be within a distance smaller than 0.05 AU between the nodes of comets and the swarms' orbits. We also consider the other possibilities to check whether the type of impact may produce outbursts. In particular, the minimal orbit intersection distances (MOID) between the swarms and the corresponding comets were calculated. For 294 comets, these values are less than 0.01 AU; and, for 14 comets, they do not reach even 0.001 AU. As an additional data source, we used the most recent data for 34 comets and considered a more rigid critical distance (0.01 AU). The results of calculations suggest that the impact mechanism may be regarded as one of the main causes of outburst events in comets. In this light, the data on comet 17P are analyzed.