(meteorobs) Ursids in 2004

[Richard Taibi]

ESKO, judging by US data, it looks like your calculations were on target!  I 
saw 3 URS in 20 minutes during the 10-11 UT period and there is more 
complete data (Stone and Gray) for 12-14 UT.  Very impressive.   Rich

>From: Esko Lyytinen <esko.lyytinen at jippii.fi>
>Reply-To: Global Meteor Observing Forum <meteorobs at meteorobs.org>
>To: meteorobs at meteorobs.org
>Subject: (meteorobs) Ursids in 2004
>Date: Mon, 20 Dec 2004 10:31:08 +0200
>
>We have computed with Markku Nissinen old trails from the Ursids parent 
>comet 8P/Tuttle, in order to trying to find good encounters for this year.
>
>
>
>The trails possibly involved are about a thousand years old, so even the 
>comet motion is quite uncertain. We report now what we have found. The 
>encounter with the trail from 1048 looks promising at first. It however 
>appears that the da0 is too big for good number of visual meteors produced. 
>An analogy with the Leonids model gives the ZHR around 1 or smaller. This 
>encounter is in December 22 at about 01 to 02 UT.
>
>
>
>Older trails from 801 to 856 seem to give meteoroids near the Earth orbit 
>at roughly the end of this year.
>
>These very old trails are very strongly scattered and the trails look in 
>the graphs that I made like scattered clouds. In general the Earth 
>encounter seems to be in the center of these wide clouds. For some reason 
>it however appears that much of the surrounding regions, both in time and 
>in rD, are more occupied than the near Earth region.
>
>
>
>These encounters happen almost half a day after the 1048 encounter. There 
>are first, at about 10 to 11 UT,  encounters with the trails 829 and 843 
>with small meteoroids (quite a big da0) and then from about 11:30 to 14 UT 
>with somewhat bigger meteoroids from the trails 801, 815, 829 and 856. The 
>trail 829 has clearly sections in both these groups.
>
>
>
>Even if the comet motion were accurate enough in our backward integration, 
>we do not give any clear prediction of outbursts even from this old trail 
>grouping. The rates are probably very low. We give the times however for 
>those wanting (if being able) to try to observe.
>
>
>
>It may even be that if the comet motion is slightly off from our nominal 
>solution, there may be higher rates from these trails and/or from some
>others. There can also be activity from even older unmodeled trails.
>
>
>Clear skies etc
>
>Esko Lyytinen
>
>Markku Nissinen
>
>---
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