(meteorobs) Re: Major Shower Peaks? -> Lyrids 2005

[Esko Lyytinen]

Hi,

I have here some data and opinions of this year Lyrids possible weak 
outburst.
As told by Mikhail, the 1-rev. trail is predicted to pass at a distance 
of about 0.0017 AU (inside the Earth orbit). This is quite nearby, but 
still probably too distant for a good outburst to appear. Looking at the 
sketched profile in the ICARUS paper ( Meteor outbursts from long-period 
comet dust trails, Lyytinen, Jenniskens, 2003 ), the 1-revolution trails 
are expected to be quite narrow. The sketch is made from Lyrids and 
Aurigids outburst data, without taking into account different sized 
meteoroids. Reading from this, one would get the ZHR of about a dozen 
(above the annual). The data points are however from outbursts of 
somewhat bigger particles, both with the Lyrids and Aurigids than those 
encountered now. So I expect the trail to be somewhat more wide than in 
the figure, but then also have a smaller peak value. Taking the 1982 
observation as a reference, I would however expect the rates to be a 
little higher than one dozen, maybe two dozens (over the annual)?
These meteors are expected to be not bright, sorry for the moon 
interference.

The timing of this encounter is expected to be quite accurate. ("The 
1922 and 1982 outbursts occurred only 6±6 and 9±3 minutes earlier than 
calculated.", reads in the ICARUS paper.) This is now at sol.long 31.964 
(J2000.0) that converts to April 22 at 01:34 UT.
This encounter is not mentioned in the paper Table, because considered 
too distant. I however expect now that someting form this trail may be 
observed and I am thankful to possible observers. This will help to map 
the 1-rev. trail, among others.

Besides this, some weaker outbursts not connected to the 1-rev. trail 
have been observed in some of the years when the 1-rev. trail passes 
quite nearby. We can however not give any real predictions. To do this, 
the parent comet motion ought to be well known two revolutions back (for 
two 2-rev. tral perediction) from now, which it is not. Old trails are 
not expected to give outburstst with long-period comets, these will soon 
get very scattered.

If any outburst of this kind (from older than 1-rev. trail) will appear, 
I can not tell the timing but expect it to be within some hours from the 
1-revolution encounter, but there might be the possibility of even more 
time difference.  On the other hand these can possibly be even quite 
close or possibly even at the same time.

Esko


 >Date: Sat, 26 Feb 2005 10:11:09 +0600
 >From: Mikhail Maslov <ast0..>
 >Subject: Re: (meteorobs) Re: Major Shower Peaks?
 >To: Global Meteor Observing Forum <meteorobs..>
 >
 >Hello, all
 >
 >I think, despite the Moon, some special attention is needed to the
 >Lyrids this year. From Esko Lyytinen's calculation 1 rev. trail in
 >April 2005 should be at 0.0017 AU from Earth. It is fairly close,
 >also, there is a possibitity of older trails encounters (not computed
 >by Esko). In SOME past similar cases Lyrids gave outbursts with
 >ZHRs up to 100, why not this year? There no garanteees, of course,
 >also the Moon will disturb greatly, but any somewhat significant
 >enhancement should be seen even in these unfavorable conditions.
 >
 >Best regards, Mikhail Maslov


 >> Does anyone know the peak dates for most of 2005's major meteor 
showers? I
 >> like to plan days off to stay up all night watching, and the earlier I
 >> request
 >> the days, the better my chances of getting them.
 >> Thanks in advance,
 >> Anthony