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(meteorobs) Re: LEONID METEORS IN 1996
I was sent this message today from Joe Rao...perhaps others will find it
interesting?
George Z.
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In a message dated 96-11-08 00:34:30 EST, you write:
<< Subj: Fwd: LEONID METEORS IN 1996
Date: 96-11-08 00:34:30 EST
From: Skywayinc
To: LI skies, JBortle, KevTK, DUrban1, GeoZay
To: Mr Astro, jrendtel@aipdot de
CC: kbeatty@skypubdot com, amacrobert@skypubdot com
CC: lrobinson@skypubdot com
According to Dan Green, the Leonid URL isn't quite right and should actually
read:
HTTP://Prometheus.arc.nasadot gov/users/leonid/www/
Nonetheless, what is mentioned in my original transmission worked for me. .
. so may'be they are both right!
-- Joe
-----------------
Forwarded Message:
Subj: LEONID METEORS IN 1996
Date: 96-11-07 10:30:07 EST
From: Skywayinc
To: BMARSDEN@cfa.harvarddot edu
CC: DGREEN@cfa.harvarddot edu
In regard to the upcoming Leonid Meteor Shower, it is of some interest to
compare the orbital geometry of the Earth to the Leonid comet
P55/Tempel-Tuttle, relative to similar past apparitions. In terms of P-E
(the minimum distance between the comet's orbit and the Earth) the current
value of -0.0080 AU is most nearly similar to 1930 (-0.0062 AU) and 1864
(-0.0065 AU). The current value of Delta-T (the number of days the shower
leads on the parent comet) is 473.1 as compared to 609.8 in 1930 and 430.7 in
1864.
The undersigned has computed that in 1930, the Earth arrived at the
descending node of P55/Tempel-Tuttle on November 17.270 UT. In this
particular year, Prof. Charles P. Olivier indicated Leonid rates, ". . .
considerably over 100 per hour, despite moonlight," adding that this display
contained, ". . . many brilliant meteors with long-enduring trains." (Flower
Observatory Reprint, No. 8/1931, pgs 1 & 35). Corroborating what Olivier
observed is a report from Prof. C.C. Wylie, Iowa City, Iowa, who estimated
maximum hourly rates of 120 shortly before dawn on November 17 (G. Kronk,
Meteor Showers -- A Descriptive Catalog. Enslow/1988). According to the
International Meteor Organization, the 1930 Leonids had a ZHR of 123.
In 1864, the undersigned found a terse reference to a ". . . brilliant
display" apparently observed from Malta (Sky & Telescope, 23, Feb. 1962, page
64). Yet, a computation of the nodal crossing time for 1864 shows Nov.
13.569 UT, suggesting that whatever enhanced activity was seen from Malta,
came either 12 to 14 hours before or after the Earth's arrival at the comet's
descending node. In sharp contrast, from England, W.F. Denning noted a
maximum hourly rate for 1864 of just 21 Leonids on Nov. 12 ( P. Roggemans,
Handbook for Visual Meteor Observations, Sky Publishing, 1989, pg. 162).
In 1996, the Earth will again cross the node of 55P/Tempel-Tuttle on Nov.
17.306 UT. In the October 1996 issue (24-5) of WGN, Peter Brown notes that:
"The time of the apparent (Leonid) peak observed in 1995 was at solar
longitude 235.5 degrees, which corresponds (1996) to 12h UT on November 17.
Enhanced activity is most likely in the interval from 0h to 12h on November
17."
For those who are interested, more information concerning past and future
Leonid apparitions can be obtained from:
HTTP://www-space.arc.nasadot gov/~Leonid/
Joe
Rao
Skyway,
Inc.
Levittown,
N.Y. >>