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Re: (meteorobs) Ursids: no outburst seen from France
> I also had a little question: Why do Ursids outbursts hapenned six years
> after the comet Tuttle reached perihelion whereas the Leonids whose
> outbursts allways occured the year the comet passes closed the Sun?
Unlike the Leonid situation, fresh trails from P/Tuttle are too far
away from the earth orbit for any close encounter. However, with the
centuries perturbations by the large planets and tend to press them
a bit inward, so that they can encounter earth. This takes about 6
centuries. During this long time, even slow particles are nearly
spread around the whole orbit, and it just requires one of these rare
narrow encounters with a trail to get an outburst - and it is not
important that the comet is nearby . Many particles, including this
year's, are also trapped in a resonance effect with Jupiter, which
concentrates them a bit in a certain part of the trail. This part is
nearly opposite of the current position of the comet in its orbit.
Hartwig
H. Luethen
h.luthen@botanik.uni-hamburgdot de
priv: Behnstr. 13, D-22767 Hamburg
lab: Institut fuer Allgemeine Botanik, Ohnhorststr. 18
D-22609 Hamburg, Germany
Tel: 0049 (0)40-3800551 priv
0049 (0)40-428-16-346
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