Correction for 8 revolutions trail from Esko Lyytinen:
Hi all,
The encounter with this trail was noticed at a quite late state of the WGN paper development. I found it in the trail data computed for the 2000 encounter. It appeared only at the highest applied nong-gravitational value (of 23 millionths of speed increase at each perihelion). I wanted to include it even though I didn't have time to study it more closely before submitting the paper.
Now I started to study how much still more far in the nong-gravitational effect range this situation will stay. To my surprise I noticed, what I had forgotten, that the modeling for the year 2000 was done in the B1950 frame. I now converted the solar longitude into UTC time according to the 2000 eqx. So the timing of this trail encounter became too early by about 0.7 day.
Instead of the early 19. the actual timing is at about 16:50 UT of this day!
Even though the computed data of this trail is yet quite scarce, as to the complete non-gravitational effect-range, I found that the trail is quite complex. It has an encounter situation also at the smaller parameter value of 16 and also with some negative values. I made a complete spreadsheet 'A2-model' even though barely enough computed data for this. This gives the main maximum a ZHR of about 70 . at sol.long 236.888 (around that 16:50 UT). The main maximum with a width of about two hours extends even more with a declining ZHR around or below 10 and rises to a new weak maximum of about ZHR 10 at 03:30 at Nov 20. This last one is from the negative 'continuos accceleration' value particles. Don't know if this second maximum can be actually identified. It is however interesting to note that the 4-rev trail in 1999 and the 7-rev. trail 'second peak' in 2001 are expected to have been caused by particles with quite large non-gravitational effects and both these peaks appeared a! s stronger than the model would predict.
The strongest 'main-maximum' is not far from the Jenniskens & Betlem filament timing and can be considered as part of this, I think.
I am sorry about my error! But I am glad that this trail may cause a stronger display than thought previously, although in a different geographical region.
Esko
Picture 1. Predicted maximum for 8 rev trail
Back to main page