The 1998 Leonid Meteor Shower
Although there was no meteor storm (defined as >1000 meteors/hour), there was quite a spectacular meteor shower in 1998. The graph below is a representation of equivalent visual meteor influx (using corrected Zenithal Hourly Rates), and was drawn using Learmonth observations and preliminary International Meteor Organisation data.
The curve assymetry shows clearly a fast rise to maximum with a slower decay. The peak influx was a little over 500/hour at around 0300 UT on November 17, and the half width of the peak about 10 hours. All of these values were substantially different from those predicted. The most quoted computer simulations, form the University of Western Ontario, had a peak flux of 1200/hour, a peak time of 17/1920 UT and a half width of an hour or two.
Observers from Jordan through Europe to the Canary Islands were the best placed to see the pinnacle of this shower. However, observers from all around the world with clear skies were delighted by the larger proportion of bright meteors and long enduring trains. At Learmonth, Western Australia, the brightest meteor seen was a magnitude -14 fireball, brighter than the full moon, and the longest train persisted for 10 minutes.
Hopefully the wealth of observations will help the computer modellers refine models of the stream of debris left by comet Tempel-Tuttle during its perihelion passage last February. However, even these results represent only a very limited spatial sample of that required to forecast with much improved accuracy.
Material prepared by John Kennewell