[meteorite-list] Dazzling Display: Early Results of the Leonid Meteor Shower

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:06:16 2004
Message-ID: <200211191710.JAA15571_at_zagami.jpl.nasa.gov>

http://space.com/spacewatch/leonids_results_021119.html

Dazzling Display: Early Results of the Leonid Meteor Shower
By Robert Roy Britt
space.com
19 November 2002

PHILADELPHIA - Early this cold November morning the Leonid meteor shower
wowed skywatchers as tiny bits of comet debris streaked in from space and
created intoxicating blurs of light.

"What a show!" said Phillipe Ayres, who watched the event with his family in
Port St. Lucie, Florida. "Even though it was cloudy at times, we were able
to see many green fireballs streaking across the heavens."

Ayres told SPACE.com he counted about five meteors per minute around 4 a.m.
local time, but by 5:45 "there were too many shooting stars to count. The
colors were bright and clear with momentary smoke trails."

Even under city lights, the Leonids put on a dazzling display, though some
observers expressed disappointment over dim shooting stars and a show that
was not as impressive as last year. The spectacular storm of 2001 may have
left some folks jaded, however. Mixed reactions to this year's version of
the annual event also seemed to be based on local viewing conditions.

During one five-minute period under a slight haze in the suburbs of
Philadelphia, 16 shooting stars graced a patch of the night that was roughly
30 percent of the entire sky, surrounded by trees. A rough projection
indicates that during the peak of activity, between 5:30 and 5:45 a.m. EST,
an hourly rate 300 to 400 shooting stars, perhaps more, should have been
visible to an observer with a view of the entire sky in this part of the
country.

Skywatchers in rural eastern locations should have seen even higher rates.

The peak was forecast to occur at 5:30 a.m. EST. Astronomers had expected
hourly rates to approach or exceed 600 for rural areas. Many residents of
the East, where the show was expected to be at its best, combated thin haze
or in some cases thick cloud cover.

Glowing reports

Observers on a SPACE.com message board gave glowing reports, one calling it
the "best shower I've ever seen." Though some people reported seeing bright
fireballs, this year's storm seemed generally to be a bit lacking in these
impressive, super-bright meteors compared to previous years, many people
noted.

However, many of the meteors seen by several observers were as bright or
brighter than Jupiter, which shone brilliantly and hung near the point in
the constellation Leo from which the meteors appeared to emanate. Many
skywatchers who braved the cold until dawn also saw Venus, the incredibly
bright "Morning Star" that rose in the south-southeast just ahead of the
Sun.

Activity seemed to be rather slow leading up to the peak, then for a short
stretch - 15 minutes or less, many people said - the pace was furious.

On an electronic meteor observing list called Meteorobs, Kim Youmans,
watching from Georgia, reported sometimes seeing "six and seven meteors in
less than 5 seconds." In San Diego, Joseph Assmus talled 250 Leonids in 3.5
hours. Most were faint, he said.

"Overall, I was struck by the lack of brilliant meteors this year," said
Gary W. Kronk, an experienced meteor observer. Kronk watched from Illinois
and counted 94 shooting stars during one 15-minute period, posting his
report on Meteorobs.

>From the desert outside Tucson, Arizona, an avid skywatcher sent SPACE.com
this report: 504 meteors between 2:45 AM and 4:30 AM local time, and a rate
that climbed to about 50 per minute in spurts centered around 3:30 AM.

As many as 75 percent of the shooting stars that would have been visible
were outshone by the Moon, astronomers had predicted before the event.

A full analysis of the spectacle won't be completed for days. Europeans were
to see a good show, forecasters had said, while North Americans were thought
to have the best seats.

Behind the shower

The Leonids occur every November, when Earth passes through a complex
network of dust streams laid down by a comet called Tempel-Tuttle. The comet
rounds the Sun every 33 years, and on each pass through the inner solar
system it leaves a fresh stream of particles in a slightly different
location. [The Science of the Leonids]

Over centuries and millennia, these streams all spread out, mingling and
creating a giant river of stuff ranging in size from sand grains to marbles.

In normal years, Leonid meteor rates top out at a few dozen per hour, or
near one per minute. Only when our planet travels through a dense stream put
down relatively recently can outbursts like this year's occur.

This morning, Earth waded into the middle of streams that Tempel-Tuttle had
deposited in 1767 and 1866. The older stream was to generate a peak of
activity over Europe at around 0400 UT. The newer stream fueled the more
active North American peak. Other bits of debris that had been drifting
through space for thousands of years also contributed to the show.

Timing dictated that people in Asia and the Southern Hemisphere were not
well positioned for this year's grand displays.

What's next?

No significant Leonid storms are expected again until 2033 or later.
Another major storm won't likely occur until at least 2098. Meanwhile,
the Perseid meteor shower, an annual August event, could kick up to
storm level in the year 2028.

This year's Leonid display will tail off quickly now. Only a sprinkle of
shooting stars will be visible each hour between midnight and dawn Wednesday.
The next chance to see a nice meteor shower will be on Dec. 14, when the
annual Geminids are expected to put on a fine display.

Editor's Note: This story was updated at 9:22 a.m. and will be updated
again later today as more reports roll in.
Received on Tue 19 Nov 2002 12:10:36 PM PST