Chaos maps and study of the Geminids meteor shower – Ariane Courtot (Observatoire de Paris)


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Meteor showers originate from a parent body, an asteroid or a comet. This parent body ejects several meteroids, forming a meteoroid stream, which will then meet the Earth. From Earth, several meteors can then be observed. To prove they form a shower, we then need to prove whether they come from the same source.

Today meteor showers are usually found without extensive study of their dynamics prior to the close encounter with the Earth. Chaos maps describe stable and chaotic regions, they are quite standard tools to study dynamics but have not been much used for meteor showers.

They are drawn using a chaos indicator. I studied 5 of them: Fast Lyapunov Indicator (FLI), Orthogonal Fast Lyapunov Indicator (OFLI), FLI for close encounters, Mean Exponential Growth Factor of Nearby Orbits (MEGNO) and mean MEGNO. The choice of the OFLI will be explained.

Those maps were then applied on Geminids, a very well-known shower. My maps show the influence of some resonances on Geminids particles. Non-gravitationnal forces, however, complicates the picture and small particles have a different response. Finally, the eccentricity also has a high impact on close encounters with the Earth. Those results and the corresponding maps will be presented as well.

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