(meteorobs) alpha Lyncids on Dec 21?

Esko Lyytinen esko.lyytinen at jippii.fi
Wed Dec 19 05:22:46 EST 2007


Hello Jan and all,

Yes, this prediction is based on the one observed outburts of this 
possible shower by Malcolm Currie in 1971 , ( see for example a breaf 
description in P. Jennisken's paper at page 960 ( page 8 in the pdf ) 
Meteor Stream Activity IV, in pdf forma at:

http://aurigid.seti.org/AA1997.pdf
(In here a possible outburst in 2007 was expected, for the first time. This gives the years 2006 and 2007, as possible but a more deatailed traill-calculation gives the years 2007 an 2008. These were given in the Icarus paper that predicted the Aurigids outburst, don't have the reference here now)
)

The observed ( 1971 ) outburst properties were suggestive of a long 
period shower-outburst. The prediction is based on these things: First 
an outburst really happened and secondly it is of long period and 
thirdly on the observed radiant location, and timing also taken taken 
into account.
 From these assumptions the "course" of the expected on revolution trail 
near the Earth orbit can be calculated and it appears that an ecncounter 
with the Earth would now happen.

Fortunately this case appears to be less sensitive on the exact location 
of the derived radiant, compared to some other possible cases. An about 
five degree ( possibly ten degree) error in the radiant derived in 1971, 
would not nullify the prediction.

The average magnitude in 1971 was only +3.47. Now the meteors are not 
expected to be brighter (althoug to some degree dependent on the local 
altitude of the radiant). If the orbital period is aroud 1000 years, 
then there should not me much difference compared to 1971, but if it 
was, say only 300 or 400 years, then the meteors now are probably even 
more dim. Unfortunately the Moon will disturb.

As to the strenght, the maximum ZHR value that Peter derived from the 
1971 outburts was >200. We don.t know how central (and at what side of 
the Earth orbit) the trail-encounter then was, and if it will now be 
encountere a little more distant or nearby. The best quess is of similar 
strength. If an outburst will now happen, then probably an ouutburst 
will also happen next year and thes together woul  probably help to 
better fix the trail location-course. Already this year observations 
would (hopefully) give a more reliable radiant location. (One would have 
to wait the next after this maybe for 46 years.)

I would encourage to try to observe this if weather etc permits. But 
don't be dissapointed if nothing is visible. If this was not of long 
period outburst, then this prediction is totally meaningless. If 
anything would happen then good video observatios for the radiant 
location would be valuble and also very precise two station orbits.


Hope you clear skies etc,
Esko




> Message: 1
> Date: Tue, 18 Dec 2007 18:34:14 +0100
> From: "Jan Verfl" <verfl.meteors at seznam.cz>
> Subject: (meteorobs) alpha Lyncids on Dec 21?
> To: "'Global Meteor Observing Forum'" <meteorobs at meteorobs.org>
> Message-ID: <mailman.191.1197999260.13329.meteorobs at meteorobs.org>
> Content-Type: text/plain;    charset="us-ascii"
>
> Hello all,
>
> in their 2002 article "Meteor outbursts from long-period comet dust 
> trails",
> Esko Lyytinen and Peter Jenniskens predict a lot of possible
> "far-comet-type" shower oubursts
>
> The point is that one of them is to happen on Dec 21, 03:40 UT from a
> radiant close to the back feet of the Great Bear (but still 
> technically in
> Lynx, so they call it alpha-Lyncids) with RA 138, DEC +44. For European
> observers it is a rather favourable timing - for example here in Prag, 
> Czech
> Republic, the radiant will be almost in zenith, still deep night and the
> (not far from full) Moon just setting.
>
> The article does not give any information about the strenght of the 
> shower,
> but it is probably because this is much harder to obtain than the timing.
> After the fantastic success of the Aurigid prediction that was carried 
> out
> by the same people, I believe there is a strong reason to go out and
> observe! I thnik that Esko is a meteorobs-member, so he will hopefully
> correct all the misinformation I may have given...
>
> Clear skies,
>
> Jan
>
>
>




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