(meteorobs) Early bright LYRs

Esko Lyytinen esko.lyytinen at jippii.fi
Wed Apr 22 05:37:52 EDT 2015


Hi Karl and all,

I try to give some further thoughts of mine on this.
I first refer to the paper:
http://dmsweb.home.xs4all.nl/publications/icaruslp-final.pdf
And in this look for especially the Figures 4 and 5.

You can see the trail image in diffent form in this link image.
http://lyytinen.name/esko/Lyrids.gif
( This may not be a very permanent link, but I will keep this probably 
for some years. Please save the image to your own computer for possible 
later lookup, if you think such need probable.)
This displays the miss-distance along the ecliptic plane rD - rE, by 
year as the abscissa coordinate.
( Markings are at the beginning of each year.)
In the Icarus paper image 5, there are marked (the known) strongest 
showers, by year.
Some of them (the strongest), 1803, 1922, 1982 are quite clearly 
outburtst from the 1-r tral.
In long perid comets the 1-r trail is quite long in years, capable of 
producing visible meteors.

The long period comets typically do not give outburtst from others than 
1-r tral. The Lyrids is however near the lover side of the long period, 
and in this probably also 2-r and maybe 3-r trails can give weaker 
outbursts. These trails however can not be calculated, because the comet 
history is not known. The others marked are probably such.

As seen in the above linked gif-trail figure, the trail almost always 
(as long as the present one is in question)  passes inside the Earth 
orbit and just barely may reach this. All the weaker outburts seem to 
have happened when the situation is more nearby or about -0.004 au. This 
is the situation now and for a few years to come. So, there is the 
possibility of a minor outburst in these year, but can not say more than 
a possibility, bigger than in general.

The waviness in the gif-image is caused by perturbations of the planets 
(mainly Jupiter)  when the meteoroids approach the inner solar system in 
this return, for each of the meteoroids.  This (practically) same effect 
is for all particles also others than in the outburst. Because the 1-r 
trai is almost constantly inside the Earth orbit, It is probable (but 
can non be concluded for sure from this only) that some kind of filament 
from several recent orbit trails is also situated a bit inside the Earth 
orbit, by its densest part. So it it probable that even in lack of 
definite outbursts , there is some level correlation of the shower 
maximum strength with the 1-r trail location. This could maybe be 
verified from existing observations, (or possibly maybe rejected). I 
have not tried this. If this (expected correlation) is the case, then 
there would more probably be now a somewhat stronger than normal shower, 
even without a definite outburst.

As to the reported early bright Lyrids. A Lyrid early by more than for 
example one day, is most probably quite many revolutions old. These also 
are each liable to the effect seen in  the waviness in the  gif-image. 
But the spread during the many revolutions (that also caused the early 
timing), is quite a lot bigger than the amount of this waviness. 
According to this, I can not expect much (annual) correlation between 
the early activity and the activity near the maximum.  Can not prove 
this non existent either maybe by some random type distribution or 
something, but do not expect much of this.

The encouter of the 1-r  trail in 2015 happens at solar longitude 31.931 
, which is today (2015,04,22) at about 14:20 UT, (in about 5 hours from 
now when I write this).  At the miss distance of almost -0.003 au, this 
itself might give just a few units in the ZHR if any, I think.
In all the planetary effects (caused during the approach into the inner 
solar sytem now) would  shift the node of each meteoroid by about one 
and a half our earlier. So the maximum may be a little earlier (in 
sol.long.) than the average. But there may well be more random type 
effects bigger than this 1.5 hour. I think to remember that there exists 
some treatment of observed maximum time dependency, but do not now have 
such by me and do not remember by whom, sorry.

Clear skies and fine Lyrids
Esko


> Hi all meteor observers,
>
> I do not know if this event may be linked to this. But it was written in the 2015 Meteor Shower Calendar of the IMO (http://imo.net/files/data/calendar/cal2015.pdf) that Esko Lyytinen somewhat predicted that there may be enhanced rates of the Lyrid shower in 2016 and 2017, as the Earth will come close to the one-revolution dust trail from C/1861 G1 Thatcher. In 2015, such enhanced rates were not as sure, as they would probably rely on some older trails which could not be modelled as accurately as the 1-rev. trail.
> "For 2015, meteor scientist Esko Lyytinen has suggested the possibility that Lyrid rates may be somewhat enhanced, although from theoretical modelling, the chances of this seem better – if still uncertain – for 2016 and 2017. The 2015 possibility is heavily dependent on what other dust trails pass closer to the Earth than the trail established from the one observed
> return of the shower’s parent comet, C/1861 G1 Thatcher, some thing which cannot be modelled." (etracted from the IMO 2015 Meteor Shower calendar, pp.6-7)
>
> Stain tuned!
> Clear skies!
> Karl
>
>
> ----- Mail original -----
> De: "Josep Maria Trigo" <trigo at ieec.uab.es>
> À: "Meteor science and meteor observing" <meteorobs at meteorobs.org>
> Envoyé: Mardi 21 Avril 2015 14:17:57
> Objet: Re: (meteorobs) Early bright LYRs
>
> george wrote:
>
>> Maybe this may mean that we will have enhanced activity this year?  Any predictions
>> or thoughts about this?
>>   
>>
>      Richard and George,
>
>      The SPMN has also detected very bright events, and one of the
> brightest ones is posted in our fireball list:
> http://www.spmn.uji.es/ESP/SPMNlist.html
>
>      Regards,
> ***************************************************
>   Dr. Josep M. Trigo-Rodríguez
>   Tenured Scientist CSIC
>   P.I. ICE Group on Meteorites, Minor bodies, and Planetary Sciences
>   Group research goals:
> http://www.ice.csic.es/en/view_research_line.php?RID=16
>   Peer-review papers: http://www.spmn.uji.es/ESP/ICE_Meteorite_group.html
>   Institute of Space Sciences (ICE, CSIC-IEEC)
>   Campus UAB, Carrer de Can Magrans s/n, (Bellaterra)
>   08193 Cerdanyola del Vallés (Barcelona), SPAIN
>   E-mail: trigo at ice.csic.es
>   Telephone: +34 93 7379788, Ext: 933069 (lab:933081)
> ***************************************************
>
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