Burst of the 1969 Leonids and 1982 Lyrids

Radar observations of the last bursts of the Leonids in 1969 and Lyrids in 1982, carried out at the Springhill Meteor Observatory, Canada, both of very short duration, with the rates exceeding a quarter-maximum rate within 50-55 minutes, are used for a study of the mass distribution of meteoroids. In both cases the mass distribution exponents of the meteoroids in the dense clouds largely differ from the values obtained for the older populations of the streams. The highest mass exponent s approximately 2.2-2.4 is found around the peak of the activity, confirming high contribution of smaller meteoroids, and thus also a recent origin of the dense clouds. Consequences of these findings are discussed.