(meteorobs) Leonids 2001-2010
Mikhail Maslov
ast0 at mail.ru
Fri Jan 7 10:29:23 EST 2005
Hello.
I wish to introduce the first results of Leonids meteor stream
simulation. It is the analysis of possibilities and conditions of
Earth encounters with trails of the periondic comet 55P in years
2001-2010. The modelling was made for the trails of latest 12
revolutions, i.e, from the 1600 trail. I used the program by S. Shanov
and S. Dubrovsky to calculate orbital elements of ejected meteor
particles. To estimate expected ZHRs for different encounters I used
the model by E. Lyytinen and T. van Flandern, given in their work
"Predicting the strength of Leonid outbursts" with some my
alterations, made in order to adopt the model for ejection velocity
(v) instead of da0 (difference in a-semimajor axis) as well as to correct
fn function to consider factual Leonids activity during recent storms
and outbursts. The calculation considers only gravitational forces,
however, the results are on the whole in good accordance with ones of
other researchers and the reality (see "postprediction" for years
2001-2004).
I included in the forecast all encouners found within interval +/-0.007
a.u. The following trail parts were analised: the first 5 rev. trails
for ejection velocities [-50;100] m/s, 6-10 rev. trails - [-25;50]
m/s, older than 10 rev. trails - [-10;25] m/s.
There are three significant encounters in the following years till
2010. Two first ones are Leonids 2006 and 2007 cases. Results here are
in good accordance with other models, although corrected fn function
gives ZHRex=22 and 17 for Leonids 2006 and 2007 respectively. However,
there is no good observing data for very high ejecion velocities part
of fn function. So this fugures are probable very approximate. Anyhow,
these years will be very important for more accurate fn function
definition.
I also found some level encounter in 2009. The Earth will approach to
three dense parts of 1767 trail (7 rev.) The distance will be quite
large from 0.0023 to 0.0031 a.e. The total ZHRex from three encounters
(their maximum times almost coincide) is 10. I should note, that
according to my calculations, two nearest parts of 7 rev. trail arrive
to Earth's orbit appr. 30 hours before the Earth itself. It means that
even small errorrs in the calculation or sample data could
considerably influence the results. If really these parts will
intersect the ecliptic 1.5-2 days later, only one part of 7 rev. trail
will give some activity, and its ZHRex=5.
In allition I'd like to express some general considerations concerning
Leonids activity in the current century. Below are distances between
the orbit of the comet 55P and the Earth's one for different
apparitions of the former in 20 and 21 centuries.
Apparition Distance (rd-re), а.е.
1899 -0.0118
1931 -0.0063
1965 -0.0031
1998 -0.0081
2031 -0.0205
2065 -0.0178
2098 -0.0067
It can be seen, that during the next return of the comet, the distance
will dramatically increase. I suppose, there will be the next
consequences: During the 1998 return clear encounters with trails
began from 1999 (maybe in somewhat from 1998). As we know, first
Leonids outbursts began as early as in 1994. They were caused not by
separale young trails, but by the cloud of very old remnants around the
comet, which are not considered in the calculations. During 2029-2031
this cloud will also be much farther. According to G. Kronk, in 1899
maximum activity was only 40 meteors per hour. In 2031 the distance
will be almost two times greater than in 1899. So, I think the most
probable is very low or completely absent additional activity in the
years 2029-2031 - around the next comet perihelion. By the way, early
sign of the cloud activity could appear in 2025, but I think the very
best would be ZHR=25-30. In 2032 chances of some level increase are
grearer, and trail activity begins from 2033. The most favorable year
will be 2034, for which I find 9 significant encounters, 2-3 of them could be
stormy, but detail calculations are necessary. As a whole, the
period of strong activity will last until 2038, and 2039 will be
transitive to usual levels.
During 2065 return strong outbursts are very possible in 2068 and
2069, and in lesser extent in 2061 and 2070. And, around the final
return of the 21 century in 2098 strong storm is very possible in 2094
and, somewhat lesser, in 2098. All these are general figures, of
course, they need to be detailed.
2001
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
2 1932 0,00344 39,8 0,490 235,249 17.11.01 13:32 1
1 1965 -0,00212 71,3 0,849 235,286 17.11.01 14:25 2
8 1733 0,00446 9,5 0,049 236,036 18.11.01 8:16 2
7 1767 0,00047 8,0 0,149 236,114 18.11.01 10:07 856
6 1800 -0,00132 8,9 0,125 236,206 18.11.01 12:18 76
12 1600 -0,00334 0,9 0,001 236,229 18.11.01 12:51 0 empty
12 1600 -0,00300 0,9 -0,012 236,250 18.11.01 13:21 0
12 1600 -0,00298 1,0 0,003 236,256 18.11.01 13:30 0 empty
5 1833 -0,00167 9,2 0,109 236,294 18.11.01 14:24 34
11 1633 -0,00070 2,7 0,001 236,399 18.11.01 16:54 0 empty
11 1633 -0,00156 2,5 0,000 236,403 18.11.01 17:00 0 empty
9 1699 -0,00012 4,0 0,383 236,428 18.11.01 17:35 4848
11 1633 -0,00020 2,6 -0,021 236,436 18.11.01 17:47 130
10 1666 -0,00188 2,9 0,000 236,440 18.11.01 17:52 0 empty
4 1866 -0,00019 13,8 0,132 236,463 18.11.01 18:25 4073
2002
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
2 1932 0,00500 51,3 0,003 235,230 17.11.02 19:14 0 empty
1 1965 -0,00180 88,6 0,811 235,275 17.11.02 20:18 5
7 1767 0,00013 11,1 0,127 236,610 19.11.02 4:04 2132
7 1767 -0,00014 9,2 -0,004 236,623 19.11.02 4:23 71
7 1767 -0,00046 9,2 0,000 236,624 19.11.02 4:24 3 empty
8 1733 0,00491 14,3 0,006 236,651 19.11.02 5:03 0 empty
6 1800 -0,00146 10,6 0,133 236,669 19.11.02 5:29 82
5 1833 -0,00148 11,7 0,114 236,720 19.11.02 6:41 73
4 1866 0,00004 16,7 0,143 236,889 19.11.02 10:43 4779
10 1666 -0,00363 4,1 0,003 237,209 19.11.02 18:19 0 empty
11 1633 -0,00414 3,8 0,046 237,232 19.11.02 18:52 0
9 1699 -0,00274 6,3 0,003 237,322 19.11.02 21:00 0
11 1633 -0,00542 4,0 -0,004 237,359 19.11.02 21:53 0 empty
11 1633 -0,00530 4,0 0,001 237,360 19.11.02 21:55 0 empty
10 1666 -0,00578 4,6 -0,010 237,458 20.11.02 0:14 0 empty
10 1666 -0,00579 4,6 0,011 237,460 20.11.02 0:17 0 empty
2003
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
2 1932 0,00609 59,6 0,462 235,230 18.11.03 1:23 0
7 1767 -0,00407 13,8 0,002 236,893 19.11.03 16:57 0 empty
7 1733 0,00363 17,3 -0,147 236,888 19.11.03 16:50 19
8 1733 0,00392 17,8 0,003 236,910 19.11.03 17:22 0 empty
8 1733 0,00362 17,1 0,000 236,920 19.11.03 17:36 0 empty
6 1800 -0,00617 12,2 0,076 237,117 19.11.03 22:17 1
5 1833 -0,00586 13,6 0,077 237,295 20.11.03 2:31 2
4 1866 -0,00313 19,1 0,113 237,618 20.11.03 10:12 14
2004
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
8 1733 -0,00236 20,8 0,094 237,840 19.11.04 21:38 32
2005
No encounters found
2006
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
2 1932 0,00013 88,2 0,481 236,617 19.11.06 4:51 22
2007
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
8 1733 -0,00488 39,3 -0,208 235,987 18.11.07 20:01 0
2 1932 0,00034 97,9 0,444 236,106 18.11.07 22:51 17
8 1733 -0,00379 40,3 0,056 236,173 19.11.07 0:27 0
2008
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
8 1733 0,00236 45,4 0,015 238,522 20.11.07 14:28 0
2009
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
а.е м/с deg
7 1767 0,00228 42,9 0,122 234,066 16.11.07 10:36 1
7 1767 0,00253 43,1 -0,808 234,067 16.11.07 10:37 4
7 1767 0,00311 43,4 1,468 234,068 16.11.07 10:39 5
8 1733 -0,00515 46,0 0,001 238,998 21.11.07 7:55 0 empty
8 1733 -0,00530 46,0 -0,002 239,001 21.11.07 8:00 0 empty
8 1733 -0,00631 46,1 0,034 239,031 21.11.07 8:42 0
2010
rev Year rd-re ej. Vel. fM sol.long max. Time(UT) ZHR ex.
8 1733 0,00482 46,7 0,020 239,810 22.11.07 9:23 0
Михаил Маслов
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