Photometry of 1998/1999 Persistent Trails from Leonid Meteors

Surface brightness and line emission rates are derived for two persistent trails from the 1998 and 1999 Leonid meteor showers. The trails are optically thin, and in places appear as cylinders with a very dark center. This center is roughly as wide as the bright emission walls, but is as dark as the sky background. This situation is not in agreement with the simple hollow-cylinder model of shell burning. The data was acquired at the Starfire Optical Range on Kirtland AFB. The instruments were guided by a human observer onto the lingering trails of the meteors. A 5 degree wide Xybion camera, attached to the headring of the telescope, recorded the scene. The University of Illinois' sodium lidar determined the distance to the persistent trails. A 200-W copper vapor laser (CVL) was also used in an attempt to measure back-scatter from particulates in the contrails of the Leonids. Almost all of the meteors that produced lingering trails greatly enhanced the naturally occurring sodium layer at 100 km. The lingering trails generally appeared as evanescent smoke rings that evolved rather quickly, with the path of the meteor marked by a double walled, optically thin tube. A 15-minute highlight video will be presented showing the evolution of the lingering trails as well as the lidar and the CVL probing them.