Recognizing Leonid meteoroids among the collected stratospheric dust

Three chemical groups of primary "silicate" spheres < 30 mum in diameter of cometary origin were collected in the lower stratosphere between 1981 May and 1994 July. The "silicate" sphere abundances represent an annual backgro und from contributions by sporadic meteor and weak annual meteor shower act ivities. During two collection periods, from 06/22 until 08/18, 1983 (U2015 ), and from 09/15-12/15, 1981 (W7027/7029), a higher number of spheres was collected compared to other periods of the year represented by the other co llectors studied here. This study links two different data sets, viz. the N ASSA/JSC Cosmic Dust Catalogs and peak activities of annual meteor showers, and identified high-velocity cometary sources for collected stratospheric "silicate" spheres. The majority of spheres on flag U2015 may originate fro m comet P/Swift-Tuttle (Perseids), while the majority of spheres on flags W 7027/7029 could be from comet P/Halley (Orionids) or comet P/Tempel-Tuttle (Leonids). Variations in relative proportions of the Mg,Si,Ca +/- Al, Mg,Si +/- Fe and Al, Si,Ca spheres may offer a hint of chemical differences amon g high-velocity comets. Proof for the findings reported here might be obtai ned by targeted cosmic dust collections in the lower stratosphere including periods of meteor shower and storm activity.