Properties of meteors with double-peaked light curves

Abstract

Twenty-one meteors showing double peaked light curves were analysed with observations collected with the Canadian Automated Meteor Observatory tracking system. Each event has orbital information, photometry, and at least one high-resolution observation. Two distinct light curve shapes were found: sudden double peaked curves, and smooth double peaked curves. The sudden peaked curves were produced by objects on asteroidal orbits and mostly showed noticeable fragmentation, while the smooth peaked curves were produced by cometary meteoroids and predominantly showed little to no visible fragmentation. An attempt to model these meteors as single bodies with two chemical components was unsuccessful, implying that fragmentation must be included in meteoroid ablation models.

High precision meteor observations with the Canadian Automated Meteor Observatory -- Data reduction pipeline and application to meteoroid mechanical strength measurements

“…At this point, the measurements from the wide-field camera show that the bulk of the meteoroid started to rapidly decelerate, as shown in Figure 17 (around 2.5 seconds), and that this disintegration produced a second peak in the light curve. Meteors with double peaked light curves were investigated by Roberts et al (2014) and Subasinghe and Campbell-Brown (2019). However, the observed behaviour of this event does not match any of their proposed meteoroid ablation or fragmentation mechanisms.…”

“…An early study by Subasinghe et al (2016) showed that 90% of the mm-sized meteors observed by CAMO display observable fragmentation while Campbell-Brown (2017) recognized that light curves of meteors with short or invisible wakes (resembling single-body meteors) cannot be explained without including continuous fragmentation in their ablation model. In an effort to explain meteors with double-peaked light curves, Subasinghe and Campbell-Brown (2019) found that even allowing for large compositional differences within meteoroids to produce multiple peaks, fragmentation still had to be included to explain the observed span of ablation heights. These conclusions from direct observations are in accordance with classical works (e.g.…”

“…meteoroids on asteroidal-type orbits fragment in the same way and as often as those on cometary-type orbits. Subasinghe and Campbell-Brown (2019) found that meteors with doublepeaked light curves on asteroidal-type orbits usually have a very sharp second lightcurve peak, indicating that the meteoroid either disrupted or suddenly released many small grains; in contrast, meteoroids on cometary-like orbits had smooth two-peaked light curves.…”