Ariane Courtot (IMCCE, France)

Title: Chaos in the Geminid Meteoroid stream

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

But dynamically linking a meteor shower with its parent body can be challenging. This is in part due to the complex dynamics of meteoroid streams and the influence of non-gravitational forces (FNG).

We develop a method to study chaos in meteoroid streams and apply it to the Geminid meteoroid stream. We choose to draw chaos maps, which relies on chaos indicator. We show that the best one is the Orthogonal Fast Lyapunov Indicator, after comparison with the Fast Lyapunov Indicator, the FLI for close encounters and the Mean Exponential Growth factor for Nearby Orbits.

We apply this method on the Geminids, a well-known meteoroid stream. We show the influence of mean-motion resonances with the Earth and with Venus, which tend to trap the largest particles. The chaos maps present 3 distinct regimes in eccentricity, reflecting close encounters with the planets. We also study the effect of NGFs and we determine a first approximation of the particle size needed to counterbalance the resonances with the diffusion created by NGFs.

The seminar will take place in room S08 at the Faculty of Sciences