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Re: (meteorobs) Dashed Leonid Hopes
Robert H. McNaught
rmn@aaocbn.aaodot gov.au
On Mon, 3 May 1999, Mark Davis wrote:
I wrote:
> Although I don't think the Americas will see the peak, it is important
> for the IMO global analyses that observations be made from all longitudes.
> Whereas predictions can be made for dust trails, there is currently no
> overall model of the background and this will require observations
> throughout the activity period to have the data for checking and models of
> the background. ^^^
This should be "ANY models of the background. I should just elaborate
that the background Leonid activity occurs for several days and is the
result of dust trails that have lost their structure through close
approaches to planets, or of particularly high velocity ejecta from the
comet that lies significantly outside the many body of a dust trail. An
example of the latter is dust from nuclear jets.
Thus, although I believe Leonid storms are well predictable, this only
applies to various causes like the resonant fireballs and the non-resonant
parts of dust trails. Enhanced background activity is always a
possibility and could occur a day of so either side of any dust trail
storm.
Note also that the Earth passes SEVERAL dust trails at various distances
in this and subsequent years. Observation of Leonid activity at the times
of closest approach to the more distant trails will help define the radial
density profile of the dust trails. So although seeing high rates might
be every meteor observer's dream, there is valuable science to be done
outside the peak period.
Cheers, Rob
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