(meteorobs) Perseid outburst prediction this year?

Tue Jun 1 04:11:40 EDT 2004

Hi, 

The timing of the 1-rev. encounter is expected to be good within about
15 minutes or better. The prediction of strength is more uncertain than
the timing.

There is a short mention in the WGN abstract (
http://www.metaresearch.org/solar%20system/perseid/perseids.asp 
down from the first abstract at the page ) of possibly increased rates
even during the annual peak, because of Jupiter perturbing the whole
stream now more close to the Sun by about 0.01 AU. This may be of more
interest in parts of the USA.
There may not be existing conclusive historic evidence on the existence
of (inreased rates because of) this phenomenon that should repeat every
12 years ( and every 30 years because the effect of Saturn, next time in
2009).

The 4-rev. trail is intersting, because in 1479 the comet orbit q-value
vas smaller than (almost) in any year when it can be reliably modeled,
before the 1862 return. In the return at 59 AD, it maybe had an about
similar value.

During some of the nearby years from now, the mean anomaly factor
however is very small. In spite of this, very good encounters would
probably give a good outburst, but no storm(?). A more dense modeling of
the trais shows that in this year it passes by about 0.005 AU inside the
Earth orbit, being probably quite indistinguishable. Next year is
better. The trail will pass within about 0.0008 AU and probably give
then some signs of its existense. The year 2008 is predicted better
(nominal miss-distance only about 0.0001 AU), with probably a good
outburst, more probably no storm although even a weak storm might be
possible. Then comes (possibly 2012 and) 2016 and then the 2028
predicted storm.
Maybe after the 2004 encounter (and after 2005) somewhat more reliable
predictions of the encouters after these can be possible.

The 2005, 4-rev. encounter is at the solar longitude of about 139.68 . A
quick look at the conversion table gives it at about 9 UT in the 12
August. This may be of interest to US-observers.

Esko

>>>

Thanks for the reply, Esko! So it appears that the Perseids will be well
worth watching this year (more so even than in recent years), both for
the likelihood of enhanced "background" activity, and the possibility of
a very short outburst on 11 Aug.

Unfortunately for North American observers, Drs. Lyytinen and van
Flandern's model predicts the possible outburst at 21h UT - the middle
of the afternoon on this side of the Pond.

Esko, you don't mention any uncertainties in this prediction - and WGN
has not yet made it across the Big Water to my doorstep yet. (If only
some kind soul would offer to print and mail copies of this Journal for
those observers doomed to live here in the Colonies! ;->)

Assuming an outburst from the 1-rev trail would actually occur, what is
the probability that it might occur in darkness for North and Central
American observers - zero?

One other quick question on your Figure 1 in the article:
    http://www.metaresearch.org/solar%20system/perseid/perseids.asp
The ecliptic crossing data points from the 4-rev trail as of 2001 are
headed in a very hopeful direction - but then they suddenly become very
sparse, so that no clear idea of their impact on, e.g., the 2004 meteor
shower can be seen. Is there any possibility of denser regions in the
4-rev trail contributing noticably to rates in 2004? Or were the
uncertainties in motion of these "old" particles just to great to make
useful predictions?

THANKS AGAIN to Esko (and any others who choose to post) for sharing
this information so freely with the community!

Clear skies,
Lew Gramer

> -----Original Message-----
> Date: Thu, 27 May 2004 10:25:22 +0300
> From: "Lyytinen Esko" <Esko.Lyytinen at MINEDU.FI>
> Subject: RE: (meteorobs) Perseid outburst prediction this year? [from
> 	IMO-News: WGN 32:2 inpress]
> To: "Global Meteor Observing Forum" <meteorobs at meteorobs.org>
>
> Hi all,
>
> I am in a little hurry in my work now. I just submitted on another 
> subject to meteorobs.
> I may write more on the Perseids later, as needed. You can now find 
> our most update brief data at:
> http://www.metaresearch.org/solar%20system/perseid/perseids.asp
>
> There is first the old annuouncement from the year 2000. Look below 
> this the new update.
>
> Esko
>
> >>>
> The latest issue of WGN (the newsletter of IMO - the International 
> Meteor Organization) is out, and among other interesting-sounding 
> items in the announcement from editor Chris Trayner, I noticed the
> following:
>
>  Perseid one-revolution outburst in 2004
>    Esko Lyytinen and Tom Van Flandern
>
> Esko is among our readers, as are several other well-informed pros and

> amateur meteor scientists. So I was impelled to ask - what ARE the 
> latest predictions for a Perseid outburst this year?
>
> Clear skies all!
> Lew Gramer, fresh back from the West Texas desert
>
>
>
> -----Original Message-----
> From: Chris Trayner [mailto:c.trayner at leeds.ac.uk]
> Sent: Tuesday, May 25, 2004 8:14 AM
> To: IMO-News mailing list
> Subject: [IMO-News] WGN 32:2 in press
>
>
> WGN - Journal of the International Meteor Organization
>
> The new issue of this Journal is now in press. It will be posted 
> shortly; subscribers should receive it soon.
>
>
> The Journal contents are below.
>
> Editorial - comics, comets and meteors
>   Chris Trayner
>
>
> Solar Longitudes for 2004
>   Compiled by Rainer Arlt
>
>
> International Meteor Conference 2004
> September 23-26 in Varna, Bulgaria
>   Eva Bojurova and Valentin Velkov
>
>
> Photographic observations of the EN291103A and B fireballs over the 
> Czech Republic
>   Pavel Spurny
>
>
> Trajectory and orbit of the EN200204 Laskarzew fireball
>   Pavel Spurny, Arkadiusz Olech and Piotr Kedzierski
>
>
> Perseid one-revolution outburst in 2004
>   Esko Lyytinen and Tom Van Flandern
>
>
> The scatter of orbital semimajor axes from a Perseid stream model
>   Kondrat'eva E.D. and Ishmukhametova M.G.
>
>
> Almost 50 years of visual Geminid observations
>   Juergen Rendtel
>
>
> The fireball stream of the Tagish Lake meteorite
>   Alexandra Terentjeva and Sergej Barabanov
>
>
> Meteor Beliefs Project: a little light anniversary entertainment
>   Andrei Dorian Gheorghe and Alastair McBeath
>
>
>
> Those who do not subscribe to this Journal, but wish to, should see 
> the IMO's web site http://www.imo.net and follow the link to WGN.
> As well as
> subscribing to WGN, you can apply to join IMO at the same time. We 
> encourage you to do this.
>
> Chris Trayner
> Editor

_______________________________________________
Mailing list meteorobs
meteorobs at meteorobs.org
http://lists.meteorobs.org/mailman/listinfo/meteorobs