(meteorobs) Perseids 2010, 1997-1999

[Mikhail Maslov]

Dear Thomas,

I responded to your main on may feraj at mail.ru yeasterday. Did you
recieve my reply? Anyway, below is its copy:

TW> according to your PER prediction website we should have been at bit closer
TW> to the core of the stream in 2010 (as in 2009, but at a much lesser extent). 
TW> Do you think this could have affected the occurence of bright Perseids, even 
TW> fireballs, or would there have been only a slight increase in ZHR numbers at 
TW> the best?

No. The big planets (namely Saturn for the 2009 case) shift the whole
Perseid stream closer to the Earth orbit, both large and small
particles. So this should lead to increase in overall meteor rates,
but the magnitude distribution shouldn't be affected.

TW> According to my own observations between Aug. 6th and 16th there were much 
TW> more fireballs than usual, even days from the maximum apart (11x -4mag or 
TW> brighter, 31x -3mag!). The only recurrences in the period 2000-2009 
TW> comparable to 2010 as for the abundance in fireballs were 2007 (resonance 
TW> zone) and 2008 (outburst from the 441 trail). In 2009 though I missed the 
TW> maximum because of bad weather.

I didn't see many reports on unsually high fireball numbers doring the
Perseids 2010 return. So perhaps you were lucky this year :). For me
both 2009 and 2010 Perseids peaks were mostly cloudy, but this year my
camera catched a -10 mag fireball through a thin layer of clouds, it
was the 11/12 Aug night.

TW> Further I'd like to know what had caused the tertiary PER peak in the years 
TW> 1997-1999 (as described in WGN)?

I didn't make detailed research on this matter. But recently I made
computations of old Perseid trails evolution (from the year ~500 AD and
earlier) and some of these old trails come close to the Earth's orbit
in 1997-1999. But I didn't calculate, how strong their influence was
and if it is enought to explain the tertiary peak occurance.

Best regards,
Mikhail Maslov