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(meteorobs) intensity distributions for the Leonids
Hi-
I'm a casual observer that comes out of the woodwork when things look
unusually interesting, as they have been with the recent Leonid showers.
Last year I was fortunate enough to have witnessed the declining hours of
the fireball shower from California's Central Valley (having driven that
night from San Francisco to someplace in the middle of nowhere near Fresno
and then over the mountains to Mojave just before dawn). In the wake of
this year's storm, which I regret I wasn't in Europe to see, I'm struck by
the paucity of fireballs. This has made me curious about how the intensity
distributions of the meteors vary both year to year and as compared between
storms and the typical display. I would have expected, not being
particularly literate in the minutiae of the Leonids, that when they storm
the percentage of brighter meteors would increase. Yet, clearly with this
storm the percentage of fireballs was quite low. Is the percentage of
fireballs observed in this year's display less than one would see during an
average display?
Much of the reason I'm curious about this is that last year I dragged a
friend along to view with me, and we drove all over in search of clear
skies, which happily we found. While I was forced by circumstance to sit at
home this year in suburbia, my friend went out to the desert near Death
Valley (Saline Valley, specifically) and viewed from there. While he saw
roughly the same numbers of meteors this year as last, they were
substantially fainter. So I've been trying to impress upon him how unusual
last year's display was, but I'm at a lack to say exactly how unusual
because I have no idea, really. So I'm turning to this list. How unusual
was it? Storms, from all showers combined, seem to happen a handful of
times per century, but how often do showers occur that are so heavily
populated by fireballs? I get the impression that although what I witnessed
last year wasn't as impressive as a storm in terms of shear numbers, it was
nevertheless more uncommon than a storm. Anyone have an educated comment on
that?
The ultimate reason I'm thinking along these lines is that in 2002 I'm
likely to be along the west coast of North America watching the Leonids
under a nearly full moon. I'm excited by this year's seeming validation of
Asher & McNaught and by their prediction for a ZHR of 25,000 in 2002, but if
the percentage of bright meteors is insignificant, what can I realistically
expect to see, even from an exceedingly remote location, given the phase of
the moon? Does the Asher & McNaught method speak to the intensity
distributions within showers? Can we predict what numbers will be seeable
with a washed-out sky?
Thanks for any responses to the above.
-Robert Hayden
(Who would so love to see any storm, but who REALLY wants to witness
something like the 1833 event, but who REALLY REALLY wants to see just one
meteor like that one in 1972...)
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