(meteorobs) Leonids 2004 failed? Maybe not...

[Mikhail Maslov]

Hello.

I want to introduce some results of checking the Leonids stream
evolution. It is is process now and complete results will be later.
But now I have to point out some interesting intermediate findings.
I did my search using the program by Shanow S. & Dubrovski S., and I
thank them very much for this possibility. From my side I created
an algorythm which enables quick generation of graphs, some pieces
of which are attached to the letter.
First of all, despite the closing Geminids I'd like to make another
return to the Leonids 2004. As we know there was a prediction of
encounter with trail of 1733 and ZHR predictions were from 30 to 60.
Some time ago I also basing of the predictions of Isao Sato tried to
make raw calculation of expected activity. I got 52, which was
somewhere among other predictions. As known, in the reality during the
expected peak time ZHR was only at 25-27.
>From my side, when I got ZHR(ex.)=52 I didn't know how mach the 1733
trail is stretched (how much fM was). In the Isao Sato predictions
this feature was not given. So I had to use some "average" value,
which, of course can lead to significant or very significant mistakes.
It became the very thing with 1733 trail. When I finished its
calculation I found that fM for necessary part of trail was only at
0.08, and ZHR calculation gives only 27-28 - much closer to real
things. Some details are on the first image attached to the letter.
Of course, such "predictions of past" are much less of interest than
before the event. But it is also important to understand the reasons
of past events.
I didn't still looked at the Leonids 2006 and 2007 cases, but this
time an encounters with young trail are predicted, so they are of much
greater confidence than in 2004.
I also want to point out the Leonids 2009. The situaltion is given on
the second image of the letter. In that year we should have an encounter
with 1766 trail. Many conditions are more favorable than in 2004,
namely it will be much closer encounter than in 2004 and this local
part of the 1766 trail is rather concentrated. I got fM~0.55 for this.
The negative feature is high velocity ejections for the particles of
this part of the trail. It is about 42-43 m/s, so any activity
increase from this trail should be from very faint meteors. But I
think they could still be in visual area, not mostly in telescopic one
as suggested for 2006 and 2007.
I can't still give ZHR predictions for this encounter, my results are
approximate. Detailed calculations will be done when I finish my work
with some other trails.
In short, I can say, that now there is no views of very strong Leonid
activity in their next return during 2030 but in 2068 I found a very
good encounter with 1932 trail. Its appropriate part is not perturbed
very much and the collision is almost ideal. Ejection velocities are
about 32-33 m/s - again faint meteors, but still acceptable. As the
trail is quite young, the activity can be very significant, not only a
storm, but a "strong storm".

Best regards, Mikhail Maslov