Meteoroid structure and ablation implications from multiple maxima meteor light curves

The Canadian Automated Meteor Observatory (CAMO) detects occasional meteors with two maxima in the image intensified CCD based light curves. We report early results from an analysis of 21 of these events. Most of these events show qualitatively similar light curves, with a rounded first luminous peak, followed by an almost linear sharp rise in the second peak, and a relatively rapid curved decay of the second peak. While a number of mechanisms could explain two maxima in the light curves, numerical modelling shows that most of these events can be matched by a simple dustball model in which some grains have been released well before intensive ablation begins, followed by a later release of core grains at a single time. Best fits to observations are obtained with the core grains being larger than the pre-released outer grains, with the core grains typically 10(-6) kg while the early release grains are of the order of 10(-)9 kg.