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RE: (meteorobs) Some Perseids above annual in 2003?


Daniel,

If we compare in the modelling the required solar radiation pressure beta value (or alternately the ejection speed) with the Leonids modelling, these would correspond an about 0.06 AU in Leonids da0 . We can compare this with the 2001 'American' outburst (7-rev.) with da0=0.08 . This would mean these Perseids to have a somewhat bigger size meteoroids population than in 2001/7rev. With this comparison one must take into account that the Perseids entry velcity is somewhat smaller than that of Leonids. I think that one may expect this Perseids encounter to contain (also) quite bright meteors.

Esko

>>>

Esko,
 
Can you say anything about the brightness of the possible additional meteors? In a DMS report I read that the maximum night in 1997 started with some fireballs.
 
Daniel van Os
 
 

	-----Oorspronkelijk bericht----- 
	Van: Lyytinen Esko [mailto:Esko.Lyytinen@MINEDU.FI] 
	Verzonden: wo 6-8-2003 8:12 
	Aan: meteorobs@atmob.org 
	CC: 
	Onderwerp: (meteorobs) Some Perseids above annual in 2003?
	
	


	The Perseids 11-revolution trail from the year 569 is expected to give
	some Perseids meteors above the annual background.
	
	The old trail is much disturbed and has a small fM-value (ie. streched
	very weak in that part of the trail). Presently, encounters to happen
	need an earlier strong effect by Jupiter or Saturn by a relatively close
	passing (within 2 AU or so) when the meteorids came to some earlier
	return into the inner solar system. After such a pass the fM will
	typically be quite small in this part of the trail in the subsequent
	returns.
	
	So the eccess now may be about a few dozens(?) The peak will be at solar
	longitude 139.82, (or between 139.81 and 139.82). This is close to, or
	some minutes past 0 UT in  August 13.
	
	This same trail may have been at least in part responsible for the new
	peak in the early 1990's and in 1997. The 1998 peak was probably caused
	by the 7-rev. trail. The cause of the clearly visible peak in 1996 is
	still unknown in spite of quite extensive searching.
	
	Hopefully we will see something even more interesting in next year
	Perseids with the one revolution trail encounter.
	
	Esko
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