OBSERVATIONS OF THE 1996 LEONID METEOR-SHOWER BY RADAR, VISUAL AND VIDEO TECHNIQUES

The activity of the 1996 Leonid shower from two radars, global visual and single-station low-light-level TV (LLTV) observations is presented and summarized. Radar observations from Ondrejov in the Czech. Republ ic indicate a peak rate of (>+1) Leonids near lambda. = 235.degrees 2/-0.1 (Equinox 2000). As observed by this radar, this peak interval wa s characterized by a significant increase in the number of bright Leon ids as demonstrated by a noticeable lowering of the mass index near th e peak. From radar observations in Ontario, Canada (using the CLOVAR s ystem), a raw peak flux of 1.3+/-0.3x10(-2) meteoroid km(-2) h(-1) bri ghter than radio magnitude +7.7 was reached at lambda. = 235.degrees 3 +/-0.1, uncorrected for initial train radius effects. Single-station L LTV observations suggest a peak shower flux of 1.8+/-0.4x10(-2) meteor oid km(-2) h(-1) brighter than absolute magnitude +5+/-0.5 between 235 .degrees 3 and 235.degrees 39. The position of the radiant on the nigh t of maximum of the shower is found to be alpha=152.degrees 9+/-1 degr ees.0 and delta=22 degrees.1+/-1.degrees 0 from CLOVAR observations an d alpha=153.degrees 3+/-1.degrees 7 and delta=22.degrees 1+/-1.degrees 7 from LLTV observations, Visual observations of the shower yield a p eak zenithal hourly rate (ZHR) of 86+/-22 at 235.degrees 17+/-0.degree s 07 or an equivalent flux of 1.2+/-0.4x10(-2) meteoroid km(-2) h(-1) brighter than absolute visual magnitude +6.5. The visual peak was shor t-lived (1.5+/-0.5 h HWHM) and richer in fainter meteors than neighbou ring intervals. Discrepancies in the estimated absolute Leonid flux fo und using differing methods are noted and possible reasons for the dif ferences discussed. The stream in 1996 showed two distinct meteoroid p opulations: a population of recently ejected meteoroids rich in smalle r particles near 235.degrees 17 which is very narrow in nodal extent ( HWHM 0.degrees 07+/-0.degrees 02), and an older component (of order IO revolutions in age) peaking near 235.degrees 4 which is rich in large r stream meteoroids, of long duration (FWHM 1.degrees 2+/-0.degrees 4) , which contributed most to the total mass flux at Earth from the stre am in 1996.