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Re: (meteorobs) Expected Lunar "ZHRs" for the Moon during 2001 Leonids



Contrary to earlier suggestions, predictions for Lunar Leonid "ZHRs"
were given by me in 2000 October and appear at

http://www.spaceweather.com/meteoroutlook/lunarleonids.html

There is a typo in that note.  For the 8-rev encounter in 2000, the peak
time at the Moon is 00:52 UT, not 03:52 UT.  I repeat the note below
with the typo corrected

Cheers, Rob

Robert H. McNaught
rmn@aaocbn.aaodot gov.au



From rmn@aaocbn.aaodot gov.au Sun Oct  7 07:54:53 2001
Date: Tue, 25 Sep 2001 22:50:15 +1000 (EST)
From: Rob McNaught <rmn@aaocbn.aaodot gov.au>
To: "Cooke,  Bill" <Bill.Cooke@msfc.nasadot gov>
Subject: Re: (meteorobs) Expected Lunar "ZHRs" for the Moon during 2001 Leonids

Bill,
I found my email.  There seem to be major differences with what you
calculate.  Have I made a big error somewhere?
Cheers, Rob

Robert H. McNaught
rmn@aaocbn.aaodot gov.au



Lunar Leonids: encounters of the Moon with Leonid dust trails.
Robert H. McNaught, Siding Spring Observatory
Last update 2000/10/26 (typo correction 2001/10/07)

The following table lists all encounters of the Moon with dust trails
within 0.0010 AU during the current epoch.  Only the trails discussed
in ref [1] are considered.  The calculations are based on the formulae
given in [2].  In every year, a test date was used to derive the
approximate magnitude of the Moon's distance towards (-ve) or away
from (+ve) the Sun in relation to the Earth (re-rm).  This was
then directly compared with values for dust trail encounters with
the Earth given in [1] and close approaches were further investigated.

An iterative process is necessary, as the motion of the Moon during
the tens of minutes between Earth and Moon encounters with dust trails
must be taken into account.

The resulting time correction (dt) from the Earth encounter time in [1]
is given along with the distance of the nominal trail center from the
Moon (rm-rd).

Finally, an approximate ZHR indicates the relative activity of these
encounters.  This is derived using the same form of analysis as in [1]
and can be compared with the predicted values for the Earth [3].  It
seems clear that 1999 was the year for lunar Leonids but the years
2000 and 2001 could have some substantial activity.

It is notable that several of these encounters are unlikely to produce
observable activity on the Earth, but as the Earth-Moon system is
passing through the midst of the comet 55P/Temple-Tuttle dust trail
complex in 2000 and 2001, several encounters occur in these years for
both the Earth and Moon.

                  re-rm            rm-rd    dt   Time of
                    AU    trails     AU     min  lunar max.        "ZHR"
1997 Nov. 18.0   -0.0018   none

1998 Nov. 18.3   +0.0027   none

1999 Nov. 18.089 -0.0009   3-rev  +0.0002  +163  Nov. 18 04:51 UT  50,000

2000 Nov. 17.327 -0.0006   2-rev  -0.0006  -175  Nov. 17 04:58 UT   1,000
          18.156 -0.0002   8-rev  +0.0010  -172       18 00:52 UT      10
          18.327 -0.0001   4-rev  +0.0009  -170       18 05:01 UT      50

2001 Nov. 17.595 +0.0022   1-rev   0.0000  +106  Nov. 17 16:03 UT     500
          18.505 +0.0020   6-rev  -0.0006  +128       18 14:16 UT   1,000
          18.595 +0.0020   5-rev  -0.0003  +130       18 16:28 UT   5,000

2002 Nov. 19.44  -0.0027   none

2003 Nov. 18.1   +0.0006   none

2004 Nov. 19.0   +0.0002   none

2005 Nov. 19.0   -0.0021   none

2006 Nov. 19.2   +0.0025   none

References
[1] R.H. McNaught, D.J. Asher, "Leonid dust trails and meteor storms",
    WGN 27, 1999, pp. 85-102.
[2] R.H. McNaught, D.J. Asher, "Variation of Leonid maximum times with
    location of observer", Meteorit. Planet. Sci. 34, 1999, pp. 975-978
[3] D.J. Asher, R.H. McNaught, "Expectations for the 2000 Leonids",
    WGN 28, 2000, pp. 134-139




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