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(meteorobs) Not another 'Leonids 2000???' thread!
HiGH!
Oh no! Not another 'Leonids 2002????' post?! I'm afraid so :) What is
written below is a full demonstration of my bureaucratic skills and possibly
waste of time, but bringing it together has made the picture in my mind a bit
clearer and I hope it will do the same to those whose picture was as fragmented
as mine. Many predictions for this year's Leonids have been made by several
very competent astronomers, but just the number of predictions and their
sometimes being contradictory to each other has begun to make a fairly
confusing picture. Three groups or individuals are now predicting the higher
peak over the US, but the trail seems to be behaving a bit oddly and the
predictions for it seem to be less confident. The fourth group, which (IMHO)
made the most accurate predictions so far, but also failed for the 4-rev trail,
predicts it to be the less strong of the two storms.
Anyway, these are the current predictions:
1. Asher & McNaught: I think these haven't been revised recently with the new
data from 2001 Leonids. I don't know how accurate the ZHR figures are.
Nov 19. 03:53UT 7-rev 3000
Nov 19. 10:29UT 4-rev 10000
2. Lyytinen and van Flandern: these have been revised very recently, as most of
you are probably aware of. In their research they have found that the 4-rev
trail seems to be 'underpowered', judging by the less than expected activity
levels during the 2000 and 2001 caused by this trail. Their current predictions
for the 4-rev trail take into account this effect, and Esko comments that if
the 'underpowered' scenario should turn out untrue, the ZHR could be up to 40%
higher. I'm not sure about the 5-rev peak strength.
Nov 19. 04:02UT 7-rev 3500
Nov 19. 06:45UT 5-rev 160?
Nov 19. 10:44UT 4-rev 2600
They seem to have predicted the strength of the 7-rev peak in 2001 very well.
Just a couple of days before the outburst, Esko made (don't know if he
published) a prediction for ZHR 1800. Which is very close to the current ~1600
level from IMO global analysis. Therefore, I am, personally, fairly confident
in their 7-rev peak prediction.
3. Jenniskens: his predictions for the last year's peak seemed off at first,
especially the 7-rev peak, where his predicted ZHR of 4200 was way off and also
the timing was off by more than half an hour. He explains the error on Leonid
MAC website: 'The 1767 dust trail (seen over the USA) was not at the expected
position, due to an encounter with Earth in a prior return. Because of this,
the lower than anticipated peak rates over the USA (factor of 2) and later than
expected peak time (40 minutes) will not affect predictions for the 2002
encounter, according to Jenniskens'. But he did get the strength and duration
of the combined 4- and 9-rev peaks with predicted ZHR 3600 and a longer total
duration than the 7-rev peak. These are his new predictions:
Nov 19. 03:58UT 7-rev 4000 +/- 1000
Nov 19. 06:22UT 5-rev 40?
Nov 19. 10:36UT 4-rev 5000 +/- 2000
4. Langbroek: Marco also made some predictions or estimates about this year's
activity, he also posted them here on 'meteorobs' saying:
- 7 revs trail ZHR 2500 minimum to 7100 maximum
- 4 revs trail ZHR 3000 minimum to 6500 maximum
....with chances best that the minimum figures are the ones to go for, he
suggests, especially for the 7 rev trail.
Ok, that's it so far. If there have been updates that I am not aware of or I
made any errors, please correct me.
Clear skies!
Jure A.
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