The limits of orbital similarity: meteoroid stream decoherence

Orbital similarity discriminants are an important tool in meteor science for identifying and characterizing meteoroid streams and meteor showers. The degree of similarity between meteoroid orbits is used to identify meteoroid streams and their associations with parent bodies. However, as many previous studies have shown, one must be careful when interpreting such similarity. For example, the widely used $D_{SH}$ criterion is mathematically not sound. In addition, thorough and careful statistical analysis is needed to estimate the probability of random association. Here we estimate the decoherence lifetime of meteoroid streams as a function of orbital elements. This is performed by generating terns of thousands of fictitious meteoroid streams and tracking their coherence over time. First results will be shown.