COMETARY DUST TRAILS AND METEOR STORMS

Meteor storms recorded during the last two centuries and cometary dust trails detected by the IRAS mission are compared with the spatial dis tribution, orbital evolution, and relative dust production of all know n periodic comets. It is shown that these two phenomena are exactly of the same nature, origin and evolution. Their parents are mainly activ e members of the Jupiter family of comets, situated on both sides of t he 2:1 resonance gap, which were not subject to closer encounters with Jupiter for several revolutions. The survival times of these compact dust streams are typically about 60 years, and the ages of the particl es forming them are still lower. Their formation, progressive asymmetr ic extension and disappearance indicates ejection velocities up to 5 m /s, and solar radiation pressure to solar gravity ratio of 10(-3). The Earth enters regions with particle density 100-times above the sporad ic background about once per century, for less than an hour. This corr esponds to a passage slightly outside the boundary of an IRAS cometary dust trail. Available data on the orbits, past perturbing planetary e ncounters, and absolute total brightness of the potential parent comet s make it possible to predict the appearance of meteor storms, and esp ecially of detectable infrared dust trails, with a relatively high deg ree of confidence.