[meteorite-list] Draconids - Part 1 of 2

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:37:33 2004
Message-ID: <3A33786F.7678B075_at_lehrer1.rz.uni-karlsruhe.de>

> On Fri, 08 December 2000, John wrote:

> My father has described to me what could be a meteorite
> storm observed in 1947 late summer evening, Barstow, Ca.

Steve responded:

> There was a meteor storm on Oct 9th, 1946 and it was widely seen here in the southwest US.
> The Draconids, this shower has the potential to produce some spectacular outbursts - and
> some have said it can equal or even exceed the Leonid storms.

> I worked with an astronomer at Lowell Observatory in the early 1970's that witnessed the Draconid
> storm of Oct 9th 1946, as well as the Leonidis of 1966 and his impression was that the 1946 event
> was much more spectacular, they were slower moving and very, very bright.

> I have read that we stand to have a repeat in 2012, not sure though - but it is worth while
> to watch this shower every October. I think that there is a slight precession in its orbit
> so it advances later into the month with each successive year.


Hello John, Steve, and List,

Here is a Sky & Telescope report about
the Draconids - also called "Giacobinids"

Sky & Telscope, October 1985, pp. 352-353:

Two Comets, Two Meteor Showers

Last month Comets Halley and Giacobini-Zinner passed within just 2 of
each other in the morning sky. This month the Earth encounters the
meteor streams associated with both. In all likelihood, nothing
spectacular will occur. But there's a small chance of extraordinary
activity, and meteor observers everywhere are on high alert.
The Giacobinid shower is the wild card. History-making meteor storms
filled the sky when the Earth passed through the wake of Comet
Giacobini-Zinner in 1933 and 1946. This year we have an outside chance
of seeing another Giacobinid storm on the night of October 7-8 or 8-9.
Later in the month a second, more predictable shower arrives, the annual
Orionids. Since the Orionids are thought to be debris shed by Halley's
comet, interest this year is particularly high.

The Giacobinid Alert

As darkness fell on the evening of October 9, 1946, many hopeful eyes
were turned skyward. Thirteen years previously Comet Giacobini-Zinner
had brought in its wake a brief, intense shower of up to 500 shooting
stars per minute. Now the comet was back, and both it and the Earth
seemed correctly positioned for a replay. Despite a full Moon, sky
watchers were not disappointed.
"By 9:15 the clouds had lifted and the cosmic fireworks began in
earnest," one correspondent wrote Sky & Telescope. "Three of us tried to
keep count [of the meteors], but after tallying 500 ceased enumeration.
There was no quarter of the heavens that was untouched by the
fireworks."
In downtown Chicago, the ABC radio network broadcast a report on the
shower live from the roof of a building where crowds of people were
counting meteors aloud. Among them was Oliver J. Lee of Dearborn
Observatory. "Meteors were flashing out every few seconds although the
sky was fully 8/10 overcast," he later wrote. "The brightest meteors
outshone Venus at her best, showed red, orange, green, and could be
followed even when their paths led behind wisps of clouds." Elsewhere, a
fireball lit up the landscape even through the moonlight. The peak rate
was estimated at 5,000 meteors per hour.
Most years produce no Giacobinids at all. An intense shower seems to
occur only when the Earth passes just inside Comet Giacobini-Zinner's
orbit shortly after the comet itself has gone by.
This year such an arrangement occurs again. However, the circumstances
are not ideal. The comet's orbit intersects the plane of the ecliptic at
a point six times farther from the Earth's orbit than in 1933, and 20
times farther than in 1946, according to Donald Yeomans and John Brandt
in "The Comet Giacobini-Zinner Handbook". So, because the meteor stream
seems to be quite narrow, it will probably miss us altogether. "It
doesn't look very good," says meteor expert Jack Drummond of Steward
Observatory in Arizona. "However, I don't think we know much about it.
Anything can happen. I'm going to be out there looking."
Unlike most meteor showers, the Giacobinids are at their best in the
evening rather than after midnight. Their radiant (apparent point of
origin) is high in the northwestern sky when darkness falls; it moves
closer to the horizon throughout the night.
Begin watching the sky overhead as soon as it gets dark. No special
equipment is needed - just an open sky, a lawn chair or blanket on the
ground, a watch, and a note pad to keep count of any Giacobinids seen.
The radiant is near the head of the constellation Draco (hence the
shower is sometimes called the Draconids). A shower member is a meteor
whose path, if traced backward, would intersect this spot.
The meteor storms of 1933 and 1946 lasted only about an hour. Yeomans
and Brandt predict that any shower this year is most likely to occur
around 13h Universal time October 8th. This is ideal timing for China,
Mongolia, and Siberia. North Americans probably have as good a chance on
the evening of the 7th as the 8th. The Moon is a waning crescent and
poses no interference.
As if the chance of a meteor storm weren't enough, Robert H. McNaught of
Siding Spring Observatory in Australia points out that the Giacobinid
stream may actually become visible in interplanetary space, shining by
reflected sunlight!
When the Earth passes through the plane of the comet's orbit, he says,
the stream of approaching meteoroids may show up as a glow stretching
westward (in position angle 263) from a point 17 due west of Altair.
The receding meteor stream would be a similar glow extending eastward
(p.a. 97) from the point on the opposite side of the sky, about 8
north of Sirius. Because of the narrowness of the stream, the effect may
not last more than several hours. Any such sighting would be an
astronomical first.

The Giacobinid meteor storm of October 9, 1933, produced rates of up to
30,000 meteors per hour. Another intense Giacobinid display is possible
- though not likely - on the nights of October 7-8 or 8-9, 1985. This
painting by pioneer space artist Lucien Rudaux was published in the
Larousse Encyclopedia of Astronomy, 1959.
Received on Sun 10 Dec 2000 07:34:55 AM PST


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