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(meteorobs) METEOR ALERT! Leonids due to peak early Monday!
I received the below message from Joe Rao this morning. Just thought I would
pass it along to the mailing list for him.
George Zay
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On Monday morning, November 17th, the Leonid meteors are scheduled to reach
maximum. This year is particularly interesting, in that the parent comet of
this particular meteor swarm -- 55P/Tempel-Tuttle -- is due to arrive at its
perihelion on February 28th of next year. Because of these circumstances,
there has been some discussion about the possibility that a meteor storm
"could" occur. In some ways, the upcoming Leonid shower does indeed bear a
similarity to the comet-Earth geometry that accompanied the Great Leonid
Meteor Storm of 1799, which was observed from Peru by the Prussian scientist
and explorer, Alexander von Humboldt.
In that particular case, the Earth led the comet to the descending node by
116.9 days. Similarly, this year, the comet follows Earth to the node by 108
days.
However. . . the respective orbits are much farther apart in 1997 as opposed
to 1799. . . the difference being 0.0048 a.u. or approximately 718,000
kilometers. Thus, the odds of a storm are greatly reduced.
Nonetheless, it will certainly be worthwhile to keep a careful watch for any
potentially unusual meteor activity; with the parent comet so close to its
nodal crossing point, there is always the possibility of a brief outburst of
activity. . . and/or some unusually brilliant fireballs or bolides. Last
year, reports received indicated meteors that left luminous trains for in
excess of five minutes. One especially brilliant meteor seen over the Canary
Islands, left a trail that lingered for nearly 30 minutes!
There are two specific time frames to be especially alert to. One is when
the Earth crosses the comet's node, which is to occur at 5:34 a.m. Pacific
time on Monday morning. Unfortunately, for those in the eastern and central
U.S., this occurs after sunrise.
The other time frame is 5:40 a.m. Eastern time. . . 2:40 a.m. Pacific time.
This corresponds to the moment when the Earth will be passing that part of
55P/Tempel-Tuttle's orbit which produced the epic meteor storm of 1966.
According to Mr. Peter Brown of the International Meteor Organization (IMO)
some slight enhanced activity has been noted near this region of space during
the last two Leonid showers. It will be interesting to see if anything
unusual is again noted this year when the Earth once again encounters this
region of space.
The major drawback of this year's Leonids will be the bright light of the 89%
waning gibbous Moon, which will positioned near Orion's upraised club --
roughly 55 degrees east of the Leonid radiant. No doubt a large number of
faint meteors will be washed-out by the Moonlight, but with the hope of
sighting some bright fireballs and bolides, it may still be worthwhile to get
out and observe. Some may use the Moon as an excuse not to get out and
observe, but this year's Leonids may be worth the effort.
Meteors appear to fan-out from the "Sickle" of Leo. The Sickle rises out of
the east-northeast around midnight and is high toward the south-southeast by
dawn. If you do go out and observe, we'd sure like to hear about what you've
seen. Good Luck!
Joe Rao
Skywayinc@aol.com