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Re: (meteorobs) Whatever happened to 'r'? (Brightness predictions for Leonids)
I had a look at this, but the data seemed too scattered and unreliable
to make any quantitative assessment. Others may have had more success.
Whereas Uchiyama's analysis assumed various r values in separating the
4-rev and 9-rev outbursts in 2001, other analyses I saw derived r values
for the overall activity. Clearly these values will be contaminated.
Plotting r against da0 and rE-rD (Sorry, don't ask for an explanation,
those that have read the papers will know what this is about. Too busy
at the moment) should show a clear relationship.
Theoretically, r should be a function of magnitude, as I see it, not
a constant value. Perhaps it is reasonably flat over certain mag ranges.
I'd think instrumental methods covering a wide mag range may be more
reliable for the determination of r, but standardisation is an issue here.
Background rates are difficult to derive when they are so much lower
than the outburst activity. It will be interesting to see what
occurs in 2003 onwards. Although not directly comparable, some idea
of the background can be gleaned from the activity post 1966 when
dust trail interactions were not important. However, the "background"
is not a physical entity like a dust trail, but an amorphous
conglomeration from multiple distant dust trail, very old diffused trails
and scattered particles. Having multiple origins, it can be treated
as a diffuse unit, but ultimately, having no simple physical form, like
a dust trail, it is less open to theoretical analysis. Various components
can be more or less active in the background in any year.
Robert H. McNaught
rmn@aaocbn.aaodot gov.au
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