Extensive meteoroid fragmentation in V/UHF radar meteor observations at Arecibo Observatory

Abstract

New 46.8/430 MHz (V/UHF) radar meteor observations at Arecibo Observatory reveal many previously unreported features in the radar meteor return that are consistent with meteoroid fragmentation. These signature features—observed at both V/UHF—include strong intra‐pulse and pulse‐to‐pulse fading as the result of interference between or among multiple meteor head‐echo returns and between head‐echo and impulsive “flare” event “trail‐echoes”. A few events are suggestive of differential ablation. These V/UHF radar observations are particularly useful as coaxial beams enable common volume observations that remove much ambiguity in the interpretation of the observations in terms of meteoroid fragmentation. These results, combined with simple modeling and two 500 sample statistical studies, lead us to conclude that a majority of the ∼17,000 AO radar meteor events included in this study exhibit fragmentation—manifested as non‐uniform lightcurves—implying that the form of meteoroid mass flux into the upper atmosphere goes well beyond simple ablation.