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(meteorobs) Data and prelim. ZHR Leonid storm LANMA
From: Marco Langbroek
Dutch Meteor Society (DMS)
Hello all,
I finally have my data of the November 17-18 Leonid storm ready. Below, I
will give a table with raw data, and:
a PRELIMINARY ZHR curve from my data for the period 1:05-4:14 UT. Reduction
procedure can be found in Peter Jenniskens paper in A&A 295 (1995), 206;
and in my paper in Meteoritics & Planetary Science 34 (1999), 137. I used
gamma=1.4 in radiant altitude correction, r=3.5 (as resulting from my
mag. estimates: 3.5 +- 0.8. No magnitude data from period 1:49-2:49!!) in
limiting magnitude correction, and my Cp is 1.4. ZHR's are only given for
radiant elevations above 20 degrees.
A fit to the ascending and descending branches gives a maximum at 2:03 UT
with a maximum activity equivalent to a ZHR of about 3200. Indeed, this is
where I have my highest count (39 Leonids in one minute at 2:03 UT, Lm
+6.6; this one minute count taken face value provides a ZHR of 3587 +-
575). With an uncertainty of only a few minutes, David and Rob's peak
prediction thus was correct. They only need to adjust their activity level
prediction model slightly!
The slopes of the peak are well defined, symmetric and suggest B=20 (see
above papers). After 3:00 UT with ZHR's below 200, there is some
indication of a background taking over.
- Marco Langbroek
Dutch Meteor Society (DMS)
table below; given are time midst (UTC), effective time of interval in
minutes; number of Leonids; ZHR ( - : ZHR not calculated, radiant below 20
degrees)
obs: Marco Langbroek LANMA
date: November 17-18, 1999
loc.: Xalos, Spain, 38d 43' 37" N, 00d 01' 30" E
-----------------------------------------
UT min Nleo eZHR
23:58 45 9 -
00:33 20 14 -
00:58 13 17 -
01:10 9 34 640 +- 110
01:22 12 71 847 +- 100
01:33 10 68 761 +- 92
01:46 8 130 1736 +- 152
01:56 9 232 2468 +- 162
02:07 8 248 2815 +- 179
02:22 7 167 1845 +- 143
02:32 7 115 1191 +- 111
02:38 6 77 928 +- 106
02:53 10 82 533 +- 59
03:03 5 39 512 +- 82
03:11 9 53 305 +- 42
03:23 5 21 251 +- 55
03:38 10 35 185 +- 31
03:46 6 18 155 +- 31
04:05 6 14 115 +- 31
04:11 6 13 105 +- 29
-----------------------------------------
note: when plotted in a diagram with the ZHR axis logarithmic,
the activity profile has a nice well defined shape! See also
the A&A paper mentioned earlier.
table: magnitude data (number of Leonids per magnitude class)
---------------------------------------------------------------
-3 -2 -1 0 +1 +2 +3 +4 +5 +6
23:35-01:49 UT 1 2 8 4 17 51 102 89 41 20
02:49-04:14 UT 0 0 5 6 11 45 80 70 38 5
TOTAL 1 2 13 10 28 96 182 159 79 25
--------------------------------------------------------------
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