(meteorobs) Maslov's Leonid predictions for the 21st century

[Mikhail Maslov]

Hello, Daniel and all,

Many thanks for your interest to my article and for the comparisons
you presented. First of all I have to say that the model I used to
calculate ZHRex is not completely main, it is based on Esko Lyytinen's
and Tom van Flandern's model, with some my alterations to use Vej
(ejection velocity) instead of da0 (difference in major semiaxis of
ejected particle and comet's orbits) and to count recent observation
results. Speaking of differences between ZHRs predicted and observed I
should say that, as follows from you comparisons, these differences
are mostly not greater than factor 2 low or high, in my opinion it is
an acceptable result. I doubt very much about principal possibility of "highly
precisive" ZHR predictions as besides computable factors such as
distance to the trail, its density, Vej of particles etc. there are
lots of other factors which are normally can't be known, for instance,
activity of the comet's core hundreds of years ago, its possible breakups,
material outbursts etc. But these factors have very strong influence on the
composition of respective trails, say, if a parent comet suffered a
loss of large pieces of its core (partial breakup), then the trail
ejected around this perihelion will be several times heavier than a
normal trail.

You mentioned predictions for 2008 outburst (I also should add
2009 case). My computations are not the only here. Principally same
results are obtained my Mikiya Sato, and we announced them on Meteorobs
nearly simultaneouly around a year ago, if I remember correctly. They
were also confirmed by Jeremie Vaubaillon. In my opinion, if orbital
elements of the comet 55P for perihelions in 15-16 centuries are
accurate enough, then our chances for significant activity are very good.

You named most, but not all years with the strongest predicted activity.
I can add (very unsure, but still interesting) 2022 (ZHR 250-300) and
2069 (ZHR 350).

Best regards, Mikhail


DF> In the current WGN (Vol. 35#1 [Feb. 2007] 5-12) Mikhail Maslov presents detailled predictions
DF> for the Leonids for the years 2007 to 2100 and 'post-dictions' for the years 2001 to 2006, but
DF> he doesn't provide a detailled comparision of the latter with what was actually observed. Here goes:

DF> Year    Date    Time seen       max. ZHR seen   Time predicted  max. ZHR pred.  the ZHR pred. was

DF> 2001    Nov. 18 10:40 UTC       2000            10:25 UTC       550 to 600      factor 4 too low
DF>                 18:20 UTC       3500            17:33 - 18:18   4400 to 5200    50& too large
DF> 2002    Nov. 19  4:10 UTC       2350             4:09 UTC       1300            factor 2 too low
DF>                 10:50 UTC       2660            10:44 UTC       4300            factor 2 too large
DF> 2003    Nov. 13 12 to 24 UTC    30              14 to 15 UTC    20 to 30        correct
DF>         Nov. 14 all day         20 to 40        14 UTC          50              probably correct
DF>         Nov. 19 0 to 22 UTC     30 to 60        18:44 UTC       15 to 20        factor 2-3 too low
DF> 2004    Nov. 17-19 plateau      35              Nov. 19 20:37   25 to 30        correct
DF> 2006    Nov. 19  4:46 UTC       75              4:55 UTC        35-40           factor 2 too low

DF> Thus Maslov's model predicts the peak times of the various dust trails very well and the activity
DF> of minor trails to within a factor of 2. His predictions for the strength of the major trails and
DF> thus Leonid storms, however, are off by factors of 2 to 4, variously over- or underestimating
DF> the peak ZHR rate. (For 2005 no IMO data are available; the model postdicts 15 to 20 on Nov. 21)

DF> For the remainder of the 21st century, Maslov's model predicts one storm with a max. ZHR of up to
DF> 1400 for 2094, six major outbursts with max. ZHR in the 300 to 500 range for 2033, 2034, 2035,
DF> 2037 and 2061, and two minor outbursts with max. ZHR of 130 to 150 for 2008(!) and 2098. Since
DF> none of the test cases covers the 100 to 500 ZHR range, we have no indication how accurate those
DF> figures may be. Nature will tell - anyone else predicting a significant shower in 2008?

DF> Daniel Fischer, Leonids veteran (see http://www.astro.uni-bonn.de/~dfischer/stories/5wildyrs ...)
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