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

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<+6.5. using 15 min binning and 0.99±0.11 meteoroids km−2 hr−1 Mv<+6.5 for 3 min intervals. The smaller temporal resolution reveals a broad plateau in flux lasting from approximately λ0=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.