Meteoroid stream identification:: a new approach -: II.: Application to 865 photographic meteor orbits

The new criterion D-N for meteoroid stream identification, based on variables directly linked to observations, is applied to a set of 865 photographic meteor orbits and the results are compared with those obtained using the well-known and widely used D-SH criterion of Southworth & Hawkins, using thresholds for meteor association computed according to Jopek & Froeschle. For 15 streams, including the Lyrids, the alpha Capricornids, the Perseids, the Taurids, the Quadrantids, the Geminids, the Leonids, the Orionids and the southern delta Aquarids, the two searches are in very good agreement, with D-N often adding a few more members to some streams, at the same level of statistical significance as used for D-SH. The Andromedids and the a Leonids, identified as populous streams using D-SH, are not recognized using D-N; on the other hand, using D-N five additional streams are identified, namely the epsilon Geminids, the Monocerotids, the northern delta Aquarids and the rather populous alpha Virginids and epsilon Piscids. In general, D-N gives results essentially equivalent to those obtained with D-SH in many circumstances, the most notable exception being for near-ecliptical streams, where the results differ markedly. We show also that the reduced distance function D-R can be successfully applied to search for meteor showers resulting from the same meteoroid stream; in our study the Quadrantids and the southern and northern delta Aquarid showers have been identified as possibly being originated by a single meteoroid stream.