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(meteorobs) Re: Leonid 'gusts' -the 1997 Japanese video!!
> Regarding these 'gusts' of Leonids; in answer to Rob questioning their
> authenticity and thinking of an origin in the observer's minds, I cannot
> help but think of the video 'gust' that the
> Japanese recorded from Hawaii in 1997 -those 150 Leonids that suddenly
> poured down in a nice little fan in just one second or so. The most likely
> explanation for that remarkable video footage, which cannot be denied
> unlike visual reports of such pehnomenon, still is the breakup of a
> meteoroid in the pre-luminous part of its trajectory. If such occasions
> are typical for 'fresh', perhaps extremely fragile dustgrains (or 'dustbals'
> cemented by volatiles -volatile sodium according to Jiri Borovicka's
> recent research results, see ACM conference) in the stream, they might be
> a general feature of storm peak activity.
My feeling is that the Japanese video is not in any way representative of
storm activity. Surely the arguments about the rates in 1966 are about
only a factor of 2 or 3, although some might argue there was a factor
of ten or more between the extreme high and extreme low estimates.
(Remember that the Milon "consensus" representes a EZHR of around
110,000 or so, as I've previously reported, not 144,000). Given
the heterogenous nature of the reports, this doesn't seem like much of a
disagreement to me. It is a well established fact that people report non
randomness in a truely random distribution. Of course, this does not
*prove* the inverse, that reports of non randomness are explained by
psychology and I'm not trying to say that. Only that such reports,
without the backup of a statistical study, need have no basis. That
meteoroids break up in the near-Earth environment and beyond, isn't an
issue for me, only the relative contribution they make and whether they
could be clearly differentiated by the observer. Had the Japanese video
event happened in a small region of the sky during the 1966 Leonid
maximum, I feel sure it would have been noted as extraordinary, especially
as there were probably many more than 150 meteors in the small region
down to the visual limit. I doubt such an event would have been repoorted
as a "flurry". Anyway, detailed analyses of the new data over the next
few years should answer this, I hope.
James Young's comment of 50 meteors visible in one second seems to be from
recollection many years later. If you look at what he wrote immediately
after the event, the numbers are much lower. I have previously quoted
this value of 50 meteors in one second (which does not equate to a *rate*
of 180,000 meteors/hour as I've mentioned before) myself. I think both
high and low values by Young appear in Littman's excellent book.
Joe: You commented that you learned of the age of the 1866 storm "last
week" after contacting David, hence my comment on the value being already
published by the Russians and David and I. It is important that Leonid
researchers be aware of the priority in Leonid and Draconid storm
predictions by the Russians (Kondrat'eva, Reznikov and Murav'eva). Their
work has been overlooked for so long.
Cheers, Rob
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