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(meteorobs) Leonids 2001 - the state of knowledge ...
... as it appeared at the annual meeting of the AKM (Arbeitskreis Meteore)
last month: Here is a story in which I summarize the collected insights.
Regards,
Daniel Fischer
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This years Leonids will be the last predicted meteor storm
in our lifetime
> With links: www.astro.uni-bonndot de/~dfischer/mirror/222.html story 7 <
If you miss the likely Leonids meteor storm this November in Eastern
Asia or Australia, don't expect another chance: The Leonids of 2002
will be swamped by the bright light of the Full Moon - and neither
the Leonids nor any other of the famous meteor streams will cause
another meteor storm in the next 50 years or so! That was one key
results presented at the annual meeting of the German Meteor Society
(AKM) at a remote lake in Brandenburg state last month, based on
extensive computer simulations by H. Luethen for various comets and
their dust trails. In 2022 there may be an impressive outburst by dust
particles shed by comet P/Schwassmann-Wachmann 3 during its
1995 perihelion (when at least two fragments split off the main
nucleus and the comet's brightness increased dramatically), but
whether the related meteor event will reach storm level is impossible
to predict.
All the eyes are thus on the upcoming 2001 Leonids outburst: There is
almost universal agreement in the meteor community now that we can
hope for a meteor storm with at least 6000 meteors per hour (thus
even exceeding the 1999 event for a single observer under perfect skies
and in the perfect spot (R. Arlt). And where would that be? The mystery
of the "early" main peak in 2000 may actually be none when one takes into
account the contributions of other dust trails to the overall profile of
meteor activity - perhaps it came only 10 minutes early (Arlt & Luethen).
In any case every one is now believing in the predicted times for the 2001
outburst: You should be in a location where the radiant of the meteors
(i.e the head of the "Lion") is high in the sky and dawn at least 30
minutes away at about 18:20 UTC on Nov.18, which corresponds to
the wee hours of Nov. 19 in East Asia and Australia.
Climate studies for the optimum viewing strip have shown a good
likelyhood for clear skies in several East Asian countries (with the
unfortunate exception of Japan) as well as Northern Australia, though
there are great differences in how the weather patterns develop (they
do so in a more predictable manner over Mongolia, China and Korea
than Down Under). A stationary observer can expect suitable
observing conditions with a likelyhood of between 60 and 80% in
various parts of Australia, 70-80% in Taiwan, 75% in Korea, 80% in
Mongolia and up to 85% in Northeast China (H. Luethen). For
logistical reasons the largest of several AKM expeditions will head to
Korea this time, with another one returning to the crumbling
observatory in Mongolia where we had been in 1998 and still others
going to Australia and China.
The wide spread of the observers (other European expeditions,
especially from the Netherlands, are also in preparation) will enhance
the chances for good data, and there is still a lot to be learned. For
example further analyis has shown that the fine structure in the
activity profile of the 1999 Leonids is not only real, but that there
is also a strong periodic signal (P=7 minutes) in the video data from
at least some geographical areas (in SE Europe), which is also evident
in radar data from Northern Germany. Wavelet analyis has confirmed the
visual impression of the data plots (J. Rendtel), and the search is on for
a physical explanation: Perhaps the parent comet's pattern of dust ejection
when it produced the 1899 dust trail responsible for the meteor storm has
been frozen in the trail for 100 years? If such a periodic structure would
return this year, we could actually learn something about the rotation of the
nucleus of comet P/Tempel-Tuttle in the 19th century ...
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