THE MASS SEGREGATION AND NODAL RETROGRESSION OF THE QUADRANTID METEOR STREAM

At the present time the longitude of the ascending node of the 'radio' meteoroids in the Quadrantid stream is 0.61 less than that of the 'visual' meteoroids. One possible explanation is that the smaller radio meteor- oids have been perturbed closer to the orbit of Jupiter than the visual ones, under the influence of the Poynting-Robertson effect. Another possibility is that they were placed closer to the Jovian orbit during stream formation. The resulting reduction of the distance between Jupiter and the stream has led to a higher value for the rate of nodal retrogression. The radio meteoroid orbit has thus precessed more than the visual one. A third possibility is that the parent comet lost the larger meteoroids before the smaller ones as it spiralled towards the Sun. A change in nodal retrogression rate with distance from Jupiter again produced the mass segregation. ©Royal Astronomical Society.