Meteoroid Clusters in Leonids

During the 2001 Leonids storm over Japan, several short-duration "outbursts" inwhich more than 20-40 meteors appeared in a few seconds, have been reported. The meteors in theseevents were extremely localized within a few hundred km, which suggest the recent fragmentationof meteoroids during the orbital motion in the interplanetary space. Considering the extent ofthe spatial distribution, we conclude that the fragmentation should have occurred at around theperihelion passage of the meteoroids just before encountering the Earth.