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J.D. Drummond, S.P. Milster, B.W. Grime (AFRL/DES), C.S Gardner, A.Z. Liu, X. Chu (University Of Illinois), M.C. Kelley, C.A. Kruschwitz (Cornell University), T.J. Kane (Penn State)
In 1998 and 1999 a campaign was conducted to study the lingering trails left by (brighter than -1.5 mag) Leonid meteors over the Starfire Optical Range near Albuquerque, NM, a facility owned by the Directed Energy Directorate of the Air Force Research Laboratory. Although not unique to the Leonids, lingering trails are characteristic of the brighter members of this shower, even in non-storm years. They are self-luminous from unknown chemiluminscent reactions involving both atmospheric and cometary species. A sodium lidar was used to probe the aftermath of several meteors, some of which left trails visible for more than 20 minutes. CCD images have been analyzed for four trails. The classical explanation of the double line appearance of many trails as shell burning in an optically thin cylinder is shown to be invalid. Surface brightnesses and line emission rates have been derived and indicate that the trails are overbright compared to non-Leonids by orders of magnitude, pointing perhaps to a compositional difference between lingering trails of Leonid and non-Leonid meteors. Because the atmospheric trajectory of the parent meteor is known, the winds and parameters of a gravity wave between 90-100 km above the Earth have been deduced from a single image taken 1-2 minutes after the meteor, or from a series of images. A five degree wide video camera was used to record the evolution of several trails, and a highlight video will be shown of this fascinating and mysterious phenomenon.