Multi-station electro-optical observations of the 1999 Leonid meteor storm

Abstract Single- and double-station video observations of the 1999 Leonid shower made from Israel are presented. A total of 232 double-station Leonids had trajectories computed. Additionally, some 2500 single-station Leonids were used to measure the Leonid storm flux and mass distribution in the interval from 0.5– 3 UT 18 November 1999. The height distribution for storm Leonids of average mass ∼10 −6 – 10 −7 kg indicates that the ablation zone is approximately Gaussian-shaped with best-fit mean begin, maximum brightness and end heights of 123.3±0.7, 107.3±0.42 and 95.0±0.56 km respectively. The peak flux at the time of the storm was found to be 0.81±0.06 meteoroids km −2 hr −1 Mv using 15 min binning and 0.99±0.11 meteoroids km −2 hr −1 Mv for 3 min intervals. The smaller temporal resolution reveals a broad plateau in flux lasting from approximately λ 0 =235.276–235.285° (J2000.0). At least one significant feature in the rate curve is apparent near 235.272°, which we suggest is associated with material released in 1932. The video mass distribution index over the course of the Leonid storm was found to be constant near s =1.75. The peak time of the storm estimated from 15 min sampling of the flux profile is near 235.283±0.005° (1h58m±7m) while 3 min resolution data place the maximum at 235.281±0.003° (1h55m±4m). The mean radiant position at the time of the storm was found to be α =153.1±0.1° and δ =21.5±0.2° (J2000), with some hint of a more compact radiant grouping within the range α =153–154° and δ =21–22°. We do not find evidence for any significant high altitude Leonid population at video masses despite biasing one camera pair to an intersection altitude of 160 km .