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Re: (meteorobs) Joe Rao's summation of the 2002 Leonids
On Sat, 23 Nov 2002, Michael Linnolt wrote:
> Jure,
>
> At the peak time of 10:47UT, my radiant height was about 8.5deg. Using the
> published IMO ZHR of 2660 and r=2.3 with my LM=5.3, that means I should
> have seen about 7 LEO in a 3 minute bin. I saw ONLY ONE LEO in the 3 min
> bin centered on 10:47UT!!! Even at 10:59, when I saw my maximum 4 LEO in
> a 3 min bin, thats less than 50% of the expected 9.
>
> There's definitely a significant under-performance from the predictions
> here!
>
> Mike
There is a major assumption here that the correction factors for radiant
elevation actually apply to the Leonids. I know Hartwig Leuven has
looked at the elevation correction for the 1999 Leonids, but it would be
useful to derive better correction parameters from such observations as
Mike's rather than rely on derived (or theoretical) parameters based
on much smaller number statistics. Note that there is more than
geometry here. The physics of the meteor is changed in that you
can't assume the same peak magnitude for the same particle for different
angle of entry, so the correction factor can be very sensitive to the
actual value of 'r'.
BTW, why would bright meteors be expected from the 4-rev trail? The da0
is getting larger from year to year and the bright meteors from the Asian
peak last year seem to have come from the 9-rev (and 10 and 11-rev) trails
and not the 4-rev as derived from Uchiyama's analysis of the 2001 Asian
peak.
Cheers, Rob
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