Results of the IMO Video Meteor Network - November 2008
=======================================================
For most European observers, November was a typical cloudy fall month
presenting only a few clear nights. Our two American observers, on the other
hand, enjoyed once more perfect conditions and collected more than 25
observing nights. Also in Portugal and parts of Italy, the weather was fine.
Our new observers Paolo Ochner and Fabio Moschini, for example, who jointly
operate a meteor camera in Albiano near the city of Trento, managed to
collected more than 100 hours of effective observing time right at the start.
As also Stefano Crivello is now operating a second camera, we have seven
cameras in operation in Italy. The number of observers is identical to
Germany (5). In Slovenia, Javor Kac is operating a fourth camera. Overall,
we collected more than 2,200 hours of effective observing time despite the
weather, which is the third best result in the IMO network. With more than
9,000 meteors, November 2008 can of course not keep up wit August or October,
but it still was the best November result to date.
No other meteor shower has spured on meteor science in the last decade as
much as the Leonids. Meanwhile, the dust trail model has been successfully
applied to predict outbursts of different meteor showers. This year, however,
it was once more the Leonids that proved the strength of the model, which
celebrated its first major success during the Leonid storm of 1999.
On November 17, 2008, at 01:30 UT (i.e. more than a decade after the last
return of the parent comet) Earth was supposed to cross the 1466 dust trail.
Therefor, Jeremie Vaubaillon predicted enhanced activity with a ZHR between
25 and 100. Visual observations were rare, because weather permitted meteor
observations almost nowhere in Europe, and the waning moon did the rest.
Still, the live activity profile of IMO confirmed a peak ZHR of nearly 100
between 01:45 and 02:30 UT.
Unfortunately, video observers were hampered similarly by the poor sky. Just
a single camera in Portugal (TEMPLAR1) enjoyed clear skies all night long,
but the moon crossed the field of view just at the maximum, so that only 39
Leonids were recorded in total. Other observers catched at least a part of
the outburst. In Berlin, ARMEFA recorded 8 Leonids between 01:30 and 02:00 UT.
BMH2 observed a total of 16 Leonids in northern Italy between 01:40 and
03:00 UT (but clouds drifted through the field of view all night long). North
of Munich, skies cleared after a shower front at 02:10 UT. Until the end of
night at 05:30 UT, MINCAM1 could record 67 Leonids under good conditions.
In Genua the clouds disappeared completely at 04:00 UT only. Until 05:30 UT,
C3P8 still recorded 37 Leonids, and STG38 11 Leonids.
Figure 1 shows the hourly Leonid rate of MINCAM1 and TEMPLAR1, corrected for
the radiant altitude. In addition, an empirical correction factor was applied
for TEMPLAR1 to account for the percentage of the field of view glared by
the moon. These data sets can only give a rough hint on the Leonid activity,
but they suggest that the outburst might have lasted longer than derived
from the sparse visual data. Between 01:30 and 05:30 UT, the Leonid rate was
enhanced, with a maximum between 02:00 and 03:30 UT.
Figure 1: Corrected hourly Leonid rates of the cameras MINCAM1 and TEMPLAR1
on the morning of November 17, 2008
What else did we learn about the Leonids from the data of the IMO network?
Accoring to the last edition of the IMO handbook for meteor observers, this
shower is active between November 10 and 23. In the recent analysis of the
video data, almost 25,000 Leonids could be identified between November 7
and 28. Thus, this shower even outperforms the Perseids thanks to numerous
video observations during the major storms of 1999 to 2002. The radiant is
well defined all the time (figure 2), from which we can conclude that the
extended activity interval is real. The radiant is found about a degree
north of the position given in the IMO handbook.
Figure 2: Radiant position of the Leonids from data of the IMO Video Meteor
Database
Between solar longitude 235 and 237, the long-term activity profile of the
Leonids (figure 3) is shaped by the different meteor storms of the last decade.
More reliable are the values away from the maximum, which confirm a roughly
symmetric activity profile.
Figure 3: Activity profile of the Leonids
Right after the Leonids, the alpha Monocerotids become active, whereby
"active" is a relative term. If we do not witness one of the rare outbursts
as in 1995, the shower is hardly noticeable. In the latest meteor shower
analysis, the alpha Monocerotids were not detected at all, and also the
list of individual radiants per solar longitude interval shows no sign of
this shower.
Instead of that, the "other" Monocerotids are present twice in the list!
According to the IMO handbook, the Monocerotids are active between November 27
and December 17. Indeed, a shower with 630 meteors was found in the video
data, whose radiant position and drift matched perfectly to the values given
in the handbook (figure 4, red). Also the velocity (41 km/s) is in agreement
with the literature (42 km/s).
The second shower in the video data was found with 850 meteors between
November 18 and December 9 (or December 7, if only times with a well-defined
radiant are taken into consideration). Thus, the activity interval slightly
overlaps with the "classical" Monocerotids. The radiant of the second
shower (figure 4, green) lies about 7 degrees north of the Monocerotids, and
both the amount and the direction of the radiant drift are identical. Yet,
with 46 km/s velocity at infinity, the second shower is slightly faster than
the Monocerotids.
Figure 4: Radiant position of the "classical" Monocerotids (red) and the
unknown meteor shower (green) from data of the IMO Video Meteor Database
The "classical" Monocerotids reach their peak activity right at the beginning
on December 7/8 (IMO handbook: December 8), and the second shower peaks at
the end of November. The peak activity level of both showers is identical.
Interestingly, also the activity profile given in the IMO handbook (blue dots)
shows not just a single maximum, but enhanced rates in early December
(figure 5). It suggests, that the visual profile covers the activity of both
showers, which is no surprise given a peak ZHR of 2 and a radiant distance
of seven degrees only. That would also explain, why according to the IMO
handbook the activity of the Monocerotids starts earlier than was found in the
video data.
Figure 5: Long term activity profile of the "classical" Monocerotids (red)
and the new meteor shower (green). The blue dots represent the ZHR profile
of the Monocerotids from the current handbook of IMO.
To verify the result, a few radiant plots were computed with the Radiant
software. The two examples in figure 6 (solar longitude 253-255 and 258-260
degree, vinf=42 km/s) prove, that there are indeed two distinct radiants.
Whereas in the first plot the northern component dominates, it is the
southern component in the second plot. We see, that the second shower is
active beyond the activity interval found by the automated shower analysis.
It confirms, that the statistical meteor shower search is limited when it
comes to such close radiants with similar velocity.
Figure 6: Radiant plot for solar longitude interval 253-255 (left) and
258-260 degree (right) given a velocity at infinity of 42 km/s
It leads us to the last question: Are these two branches of the same shower
(similar to the northern and southern Taurids) or do we observe two
independent showers? The similarity of both is an argument for a single
shower; the small, but significant difference in velocity is a counter
argument. For this reason, I tend to believe in two independent meteor
showers.
In the end, let's have a retrospect at the Taurids: Their brightness
distribution at the end of October seemed to suggest, that the Taurids of
2008 were brighter than in the years before. If the plot is extended until
November 20 with the newly available data (figure 7), this result is not
confirmed. There are indeed times where the shower meteors are somewhat
brighter than usual, but at other times they are equally fainter. Overall
there is no clear trend towards brighter Taurids in 2008.
Figure 7: Mean brightness difference between the Taurids and sporadic meteors
in the years 2006 till 2008
1. Observers
============
Code Name Place Camera FOV LM Nights Time Meteors
--------------------------------------------------------------------------------
BENOR Benitez-S. Las-Palmas TIMES5 (0.95/50) 10 dg 3 mag 14 43.4 h 89
BRIBE Brinkmann Herne HERMINE (0.8/6) 55 dg 3 mag 5 17.9 h 94
CASFL Castellani Monte Baldo BMH1 (0.8/6) 55 dg 3 mag 15 118.3 h 354
BMH2 (0.8/6) 55 dg 3 mag 22 147.4 h 478
CRIST Crivello Valbrevenna STG38 (0.8/3.8) 80 dg 3 mag 2 20.8 h 111
Genova C3P8 (0.8/3.8) 80 dg 3 mag 14 101.3 h 581
ELTMA Eltri Venezia MET38 (0.8/3.8) 80 dg 3 mag 6 52.6 h 207
GONRU Goncalves Tomar TEMPLAR1 (0.8/6) 55 dg 3 mag 22 183.1 h 1036
HERCA Hergenroth. Tucson SALSA (1.2/4) 80 dg 3 mag 28 258.5 h 596
HINWO Hinz Brannenburg AKM2 (0.85/25) 32 dg 6 mag 17 108.0 h 489
KACJA Kac Kostanjevec METKA (0.8/8) 42 dg 4 mag 14 110.6 h 303
Kamnik REZIKA (0.8/6) 55 dg 3 mag 13 79.4 h 404
STEFKA (0.8/3.8) 80 dg 3 mag 6 31.8 h 82
Ljubljana ORION1 (0.8/8) 42 dg 4 mag 13 65.6 h 180
KOSDE Koschny Noordwijkerh. TEC1 (1.4/12) 30 dg 4 mag 3 7.4 h 21
LUNRO Lunsford Chula Vista BOCAM (1.4/50) 60 dg 6 mag 26 221.2 h 1368
MOLSI Molau Seysdorf AVIS2 (1.4/50) 60 dg 6 mag 15 71.3 h 661
MINCAM1 (0.8/6) 55 dg 3 mag 22 79.7 h 221
Ketzuer REMO1 (0.8/3.8) 80 dg 3 mag 4 13.5 h 35
REMO2 (0.8/3.8) 80 dg 3 mag 4 12.7 h 35
OCHPA Ochner Albiano ALBIANO (1.2/4.5) 68 dg 3 mag 15 112.3 h 418
PRZDA Przewozny Berlin ARMEFA (0.8/6) 55 dg 3 mag 12 67.9 h 219
SLAST Slavec Ljubljana KAYAK1 (1.8/28) 50 dg 4 mag 11 58.0 h 134
STOEN Stomeo Scorze MIN38 (0.8/3.8) 80 dg 3 mag 15 92.8 h 320
STRJO Strunk Herford MINCAM2 (0.8/6) 55 dg 3 mag 9 44.9 h 153
MINCAM3 (0.8/8) 42 dg 4 mag 8 28.7 h 88
MINCAM5 (0.8/6) 55 dg 3 mag 9 40.3 h 223
YRJIL Yrjola Kuusankoski FINEXCAM (0.8/6) 55 dg 3 mag 17 73.7 h 270
--------------------------------------------------------------------------------
Overall 30 2263.1 h 9170
2. Observing Times (h)
======================
Nov 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BENOR - 2.9 5.6 - 1.0 - 3.0 - 7.2 1.0 5.5 1.0 - - 2.0
BRIBE - - 8.4 - - - 3.3 5.3 - - - 0.6 - - -
CASFL 9.3 5.1 - - - - - - - - - - - - 9.3
9.3 2.6 1.2 0.5 1.0 - - 2.7 11.7 11.7 - - - 11.8 9.3
CRIST - - - - - - - - - - - - - - 11.1
1.1 - 5.0 - - - 8.9 5.4 - - - - - - 10.3
ELTMA - - - - - - - - - - - - - 12.0 12.2
GONRU 5.2 1.8 - - 8.4 - 6.3 10.5 10.1 - - 5.1 3.1 5.8 9.5
HERCA 11.5 11.4 11.5 11.5 11.5 11.6 11.6 11.6 11.7 4.0 7.2 7.5 2.0 11.6 11.6
HINWO 10.8 1.0 5.3 - 11.9 - - 9.1 6.5 10.9 - - - - 12.1
KACJA 11.7 - 4.6 - - - - - - - 6.2 - - - 11.1
- 9.0 10.0 - 1.5 - 0.9 10.4 - - - 5.1 2.8 1.8 10.1
- - - - - - - - - - - - - - -
- 4.2 5.4 - - - - 2.4 1.7 - 1.1 - - - 4.0
KOSDE 0.5 - - - - 2.7 4.2 - - - - - - - -
LUNRO 10.8 5.7 4.2 2.5 7.3 11.4 11.4 11.3 5.7 6.1 7.2 8.4 11.4 11.6 11.5
MOLSI 9.7 - 2.4 - 6.6 - - - 3.1 9.7 - - - - 7.0
3.9 - 6.0 - 6.6 - 1.3 1.7 2.1 7.8 - - - 3.0 7.5
4.5 - - 0.2 - - 2.0 6.8 - - - - - - -
8.0 - - 0.3 - - 1.1 3.3 - - - - - - -
OCHPA - - - - - - - 2.0 8.4 9.8 - - - 3.8 10.2
PRZDA 3.3 - - - - - - 4.0 2.0 7.6 10.6 - 6.6 - -
SLAST 3.8 6.7 5.8 - - - - - - - - - - - 2.3
STOEN 10.0 - - - 5.2 1.0 - 1.3 - - - - - 12.4 12.4
STRJO 0.2 0.5 4.5 - - - 7.5 6.0 2.0 0.5 5.3 - 1.2 - -
- - - - - - 3.9 8.7 1.9 - 4.5 - 0.8 - -
- - - - - - 5.0 8.6 2.2 - 5.0 - 1.0 - -
YRJIL 7.3 3.8 2.8 8.0 4.8 7.9 - - - - - 1.2 - 1.9 -
--------------------------------------------------------------------------------
Sum 120.9 54.7 82.7 23.0 65.8 34.6 70.4111.1 76.3 69.1 52.6 28.9 28.9 75.7163.5
Nov 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
--------------------------------------------------------------------------------
BENOR 6.3 2.8 2.8 - 0.3 2.0 - - - - - - - - -
BRIBE - - 0.3 - - - - - - - - - - - -
CASFL 2.8 3.4 10.4 10.4 10.4 3.6 10.9 3.5 9.2 12.5 12.5 5.0 - - -
5.5 2.5 11.9 8.9 5.9 4.4 8.4 2.5 9.0 12.0 11.1 3.5 - - -
CRIST 9.7 - - - - - - - - - - - - - -
8.4 3.9 7.8 5.7 - 11.5 8.4 - 3.0 12.1 9.8 - - - -
ELTMA 8.1 - 6.4 - - - 10.3 3.6 - - - - - - -
GONRU 12.1 6.7 12.1 11.8 9.5 12.3 12.2 5.5 7.0 12.3 12.2 3.6 - - -
HERCA 11.8 11.6 11.2 - 11.3 11.9 11.9 10.5 11.5 2.0 6.0 - 1.5 6.2 3.3
HINWO - 5.2 3.3 1.0 - - - 1.7 - 6.4 9.2 10.5 0.4 2.7 -
KACJA - 10.3 5.2 4.8 4.4 - 11.7 6.8 - - 9.7 12.9 - 5.9 5.3
7.3 - - 12.9 7.2 - - 0.4 - - - - - - -
1.0 1.9 8.2 1.3 - - 12.1 7.3 - - - - - - -
- 10.0 4.9 7.2 - 7.4 12.4 4.5 - - 0.4 - - - -
KOSDE - - - - - - - - - - - - - - -
LUNRO 8.2 11.5 11.6 8.5 11.6 9.3 8.4 0.5 11.8 - - - - 10.0 3.3
MOLSI - 3.1 0.4 2.8 - - - - 1.2 - 4.6 11.1 3.2 5.7 0.7
3.8 6.1 0.1 1.2 - 1.0 - 0.5 0.2 0.7 6.9 11.4 5.0 1.4 1.5
- - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
OCHPA - 5.2 11.7 7.5 10.7 4.1 - 5.2 6.6 9.3 12.5 5.3 - - -
PRZDA 5.8 8.7 - - 4.2 - 5.9 - - 4.7 - - - 4.5 -
SLAST - 4.7 3.7 6.3 - 5.4 11.6 5.7 - - 2.0 - - - -
STOEN 4.6 - 2.1 5.7 - - 6.1 2.6 2.4 8.7 10.3 8.0 - - -
STRJO 2.2 - 1.5 - 1.0 0.5 - - - 0.5 - - - 6.6 4.9
2.7 - - - - - - - - 0.7 - - - 5.5 -
4.6 - - - - - - - - 1.0 - - - 7.5 5.4
YRJIL - 13.0 - 3.1 5.7 6.3 - 0.1 - - 5.6 - 2.2 - -
--------------------------------------------------------------------------------
Sum 104.9110.6115.6 99.1 82.2 79.7130.3 60.9 61.9 82.9112.8 71.3 12.3 56.0 24.4
3. Results (Meteors)
====================
Nov 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15
--------------------------------------------------------------------------------
BENOR - 6 13 - 1 - 4 - 10 1 9 1 - - 6
BRIBE - - 50 - - - 12 29 - - - 2 - - -
CASFL 45 10 - - - - - - - - - - - - 33
41 9 7 4 2 - - 8 32 45 - - - 41 38
CRIST - - - - - - - - - - - - - - 50
6 - 15 - - - 56 20 - - - - - - 54
ELTMA - - - - - - - - - - - - - 43 53
GONRU 15 2 - - 40 - 31 73 64 - - 18 4 13 43
HERCA 28 31 20 26 25 29 27 26 21 8 10 24 3 24 28
HINWO 44 1 11 - 78 - - 57 48 48 - - - - 44
KACJA 44 - 5 - - - - - - - 10 - - - 46
- 28 36 - 2 - 2 44 - - - 68 4 25 55
- - - - - - - - - - - - - - -
- 8 8 - - - - 3 6 - 2 - - - 7
KOSDE 4 - - - - 5 12 - - - - - - - -
LUNRO 87 21 21 19 35 95 108 84 11 30 51 41 43 70 70
MOLSI 80 - 20 - 51 - - - 18 64 - - - - 27
7 - 6 - 9 - 2 5 5 15 - - - 5 10
16 - - 1 - - 6 12 - - - - - - -
20 - - 1 - - 4 10 - - - - - - -
OCHPA - - - - - - - 2 41 50 - - - 10 42
PRZDA 8 - - - - - - 7 7 38 16 - 18 - -
SLAST 8 12 13 - - - - - - - - - - - 3
STOEN 36 - - - 16 4 - 2 - - - - - 45 63
STRJO 1 1 11 - - - 22 16 5 1 25 - 3 - -
- - - - - - 8 23 7 - 18 - 1 - -
- - - - - - 43 47 5 - 32 - 2 - -
YRJIL 19 14 9 32 22 36 - - - - - 3 - 3 -
--------------------------------------------------------------------------------
Sum 509 143 245 83 281 169 337 468 280 300 173 157 78 279 672
Nov 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
--------------------------------------------------------------------------------
BENOR 23 5 4 - 2 4 - - - - - - - - -
BRIBE - - 1 - - - - - - - - - - - -
CASFL 8 3 28 24 23 15 28 5 22 41 59 10 - - -
35 4 40 28 17 17 17 7 15 33 32 6 - - -
CRIST 61 - - - - - - - - - - - - - -
84 21 57 18 - 70 19 - 10 78 73 - - - -
ELTMA 13 - 45 - - - 47 6 - - - - - - -
GONRU 100 60 71 61 63 72 77 12 54 72 84 7 - - -
HERCA 37 48 30 - 24 28 21 27 17 3 15 - 2 9 5
HINWO - 16 9 1 - - - 2 - 33 32 59 3 3 -
KACJA - 42 7 11 9 - 38 10 - - 36 26 - 12 7
17 - - 101 20 - - 2 - - - - - - -
1 11 22 3 - - 36 9 - - - - - - -
- 31 16 13 - 35 43 7 - - 1 - - - -
KOSDE - - - - - - - - - - - - - - -
LUNRO 68 87 78 64 76 37 27 1 62 - - - - 50 32
MOLSI - 11 3 30 - - - - 29 - 63 171 55 33 6
95 5 1 1 - 3 - 2 1 1 13 19 10 3 3
- - - - - - - - - - - - - - -
- - - - - - - - - - - - - - -
OCHPA - 16 46 37 30 12 - 7 24 40 45 16 - - -
PRZDA 36 27 - - 12 - 16 - - 22 - - - 12 -
SLAST - 9 4 10 - 17 38 16 - - 4 - - - -
STOEN 10 - 2 8 - - 28 6 7 36 39 18 - - -
STRJO 9 - 8 - 4 1 - - - 2 - - - 25 19
9 - - - - - - - - 2 - - - 20 -
25 - - - - - - - - 5 - - - 33 31
YRJIL - 41 - 5 37 11 - 1 - - 35 - 2 - -
--------------------------------------------------------------------------------
Sum 631 437 472 415 317 322 435 120 241 368 531 332 72 200 103
Sirko Molau, 2008/12/23