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. Republic indicate a peak rate of (>+1) Leonids near lambda. = 235.degrees 2+/-0.1 (Equinox 2000). As observed by this radar, this peak interval was characterized by a significant increase in the number of bright Leonids as demonstrated by a noticeable lowering of the mass index near the peak. From radar observations in Ontario, Canada (using the CLOVAR system), a raw peak flux of 1.3+/-0.3x10(-2) meteoroid km(-2) h(-1) brighter than radio magnitude +7.7 was reached at lambda. = 235.degrees 3+/-0.1, uncorrected for initial train radius effects. Single-station LLTV observations suggest a peak shower flux of 1.8+/-0.4x10(-2) meteoroid 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 night of maximum of the shower is found to be alpha=152.degrees 9+/-1 degrees.0 and delta=22 degrees.1+/-1.degrees 0 from CLOVAR observations and 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 peak zenithal hourly rate (ZHR) of 86+/-22 at 235.degrees 17+/-0.degrees 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 short-lived (1.5+/-0.5 h HWHM) and richer in fainter meteors than neighbouring intervals. Discrepancies in the estimated absolute Leonid flux found using differing methods are noted and possible reasons for the differences discussed. The stream in 1996 showed two distinct meteoroid populations: a population of recently ejected meteoroids rich in smaller 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 larger stream meteoroids, of long duration (FWHM 1.degrees 2+/-0.degrees 4), which contributed most to the total mass flux at Earth from the stream in 1996.