(meteorobs) LEONID METEOR OUTBURST IN THE OFFING?

[Bruce McCurdy]

Thanks, Joe. Whilst the article stipulates eastern Canada, here in 
(north)western Canada (113°.4 W, 53°.6 N.) the radiant rises a little 
earlier that one might suppose, and I have hopes of maybe catching a few 
earthgrazers towards the end of that half hour. Does the filament have a 
known radiant, or should one just use the radiant of the date? Also, and I 
know this is covering old territory, but how far below the horizon can the 
radiant be and still produce possible meteors?

Thanks.

Bruce
*****

----- Original Message ----- 
From: <Skywayinc at aol.com>
To: <meteorobs at meteorobs.org>
Sent: Monday, November 13, 2006 5:58 PM
Subject: (meteorobs) LEONID METEOR OUTBURST IN THE OFFING?


> November 13, 2006
>
> Contacts:
> Alan MacRobert, Senior  Editor
> 617-864-7360 x151, amacrobert at SkyandTelescope.com
> Marcy  McCreary, VP Mktg. & Business Dev.
> 617-864-7360 x143,  mmccreary at SkyandTelescope.com
>
> LEONID  METEOR OUTBURST IN THE  OFFING?
>
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>
> Late  this Saturday night (November 18, 2006) a meteoric sky show could
> break over  New York, New England, and eastern Canada. According to SKY &
> TELESCOPE  magazine, the Leonid meteor shower -- which put on intense
> displays from 1998  to 2002 -- could return for a brief, last-gasp 
> reprise.
>
> Every  mid-November, as Earth cruises along its annual orbit around the
> Sun, we pass  through the Leonid meteor stream. Most parts of the stream
> are sparse, so we  get only a very minor meteor shower (roughly 10 meteors
> visible per hour).  But some parts of the stream are much richer. This
> year, reports SKY &  TELESCOPE meteor expert Joe Rao, specialists predict
> that we'll sail through  a narrow, dense filament of the stream. The whole
> thing should last for only  about a half hour centered on 11:45 p.m.
> Eastern Standard Time on Saturday  night, November 18th.
>
> In North America, only New England, easternmost New  York State, and
> Canada's provinces from Quebec eastward will be positioned to  catch the
> possible display. Even in these regions, the meteors will come  skimming
> into the upper atmosphere at a low angle. This means that the  numbers
> you'll see even during an outburst will be relatively low, perhaps  one
> every couple of minutes. However, the meteors that you do see  overhead
> will be long, dramatic "Earth-grazers" skimming almost horizontally.  Even
> one of these can be a sight to remember.
>
> Bundle up warmly, find a  dark spot with an open view of the sky, lie back
> on the ground or in a  reclining lawn chair, and just gaze up into the
> stars. Any Leonids you see  will be coming from the northeast. Be patient.
>
> The best place to watch  from is actually westernmost Europe. Here the
> shower will happen just before  the first light of dawn on Sunday morning;
> the predicted time of the shower's  maximum is 4:45 a.m. GMT on November
> 19th. This side of the world will be  facing more directly into the
> oncoming shower, so the meteors will fall more  nearly straight down, and
> the observed numbers should be  greater.
>
> Background
>
> The Leonid meteoroids are  bits of debris shed by Periodic Comet
> Tempel-Tuttle, and they continue to  travel in a broad stream along the
> comet's orbit. Every 33 years the comet  passes through the inner solar
> system, warms up in the heat of the Sun, and  sheds a new filament of
> debris, adding to the general meteor stream. When  Earth encounters one of
> these dense new filaments (which haven't yet had time  to disperse very
> much), we can get a very strong but short-lived meteor  display.
>
> This tends to happen around the years when the comet itself is  passing
> through. The comet's most recent return happened in 1998, so you  might
> expect that by 2006, all activity beyond the 10-per-hour background  would
> be over. But experts predict maybe not.
>
> The reason goes back  several decades. On the morning of November 17, 1969
> -- three years after a  historic Leonid storm in 1966 -- an unexpected
> burst of Leonid activity broke  over eastern North America. Some observers
> reported seeing an average of two  to four meteors per minute. What had
> caught observers off guard was Earth's  passage through a thin, relatively
> dense ribbon of dust and debris that had  been shed by Comet Tempel-Tuttle
> in 1932. The densest part of the ribbon was  less than 30,000 miles 
> (48,000
> kilometers) thick. Earth, traveling in its  orbit at 18.5 miles per 
> second,
> swept through it in only about a half  hour.
>
> In 1999 Robert McNaught and David Asher published a paper on Leonid  dust
> trails in the meteor journal WGN and cited the case of the 1969  outburst.
> They forecast that in 2006, Earth will encounter a follow-on  section of
> that very same dust trail from 1932. They predict that this  year's
> encounter will be centered on 4:45 Universal Time (GMT) Sunday  morning,
> November 19th.
>
> Other leading meteor forecasters, such as Tom  Van Flandern of the United
> States, Esko Lyytinen of Finland, and Jeremie  Vaubaillon of France, later
> confirmed this encounter with the 1932 rubble  trail, and their predicted
> times match McNaught's and Asher's to within a few  minutes, SKY &
> TELESCOPE reports.
>
> So another short-lived outburst  seems probable -- but it's unlikely to be
> as intense as in 1969. That year's  encounter came about 4.5 years after
> Comet Tempel-Tuttle passed closest to  the Sun. This year it's happening
> almost 9 years after the comet last swept  through. So we'll likely pass
> through a sparser region of the 1932 rubble  trail. A reasonable guess is
> that the resulting display will be about half as  strong.
>
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