(meteorobs) Leonids 2021-2030
Mikhail Maslov
ast0 at mail.ru
Thu Feb 17 08:14:54 EST 2005
Hello.
I wish to introduce the 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
2021-2030. 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 paper
"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.
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.
Some encounters of different level were found in the period 2021-2030.
However, we face a general condition here - the majority of encounters
are coused by trails parts with negative ej. velocities, i.e.
particles, ejected forwards by the comet, not backwards, as more
usually.
These negative velocities parts belong to the trails around the comet
perihelion in 2031, i.e. they move before the comet.
The main problem here is the lack of data. Lyytinen-van Flandern model
is built, as I understand, for positive ej. velocities. So the
question is to what extent is it usable for negative ej. velocities?
It reasonable to suggest that the comet ejects equal amounts of
particles in both positive and negative directions. However we have
also to account radiation pressure which acts as a decrease to the
gravitational constant, so far increasing orbital periods of the
particles. As a result, negative and positive trail parts are not
symmetric. In the positive area ej. velocity and radiation pressure
strengthen each other, in the negative area they act against each
other. That's the reason why positive trail parts contain much more
material comparing to negative. But how much more? Not to much data.
As I know, it is believed, that significant activity can be caused by
particles in the interval [-25;+40] m/s and stormy activity - in the
interval [-10;15] m/s. So far I calculated ZHRex for negative parts
using Lyytinen-van Flandern model and doubled absolute value of ej.
velocity. For instance, to calculate activity from encounter with
particles of ej. velocity -15 m/s, I used value |-15|*2=30 m/s.
These ZHRs are of great uncertainty, of course, but at least they can
serve as a measures of relative perspectiveness. Also it means the
high necessity of Leonid observations in 2020s to build activity
function in the area of negative ej. velocities. The most interesting
in this case are years 2022, 2024, 2025, 2026, 2027.
I'd like to pay special attention to 2028-2030 period. No encounters
are found for these years and, despite closing perihelion in 2031, I
think we have very high probability of absence any additional
activity. This probability is the highest in 2030, somewhat lesser in
2029 and more lesser in 2028. This sutuation differs from 1994-1997
periods, preceding the perihelion in 1998, the reason is in several
times greater distance between the comet and the Earth orbits in 2031
comparing to 1998.
rev. Year rd-re ej. Vel. fM(fNP) sol.long max. Time ZHR ex.
AU m/s deg UT
2021
5 1833 -0,00106 95,6 0,123 235,884 18.11.21 7:14 1
7 1800 0,00514 -19,1 0,033 238,536 20.11.21 22:48 0
2022
5 1833 -0,00276 97,4 0,002 236,075 18.11.22 18:26 0 empty
5 1833 -0,00282 97,4 -0,018 236,076 18.11.22 18:27 0
5 1833 -0,00305 97,4 0,084 236,080 18.11.22 18:32 0
9 1733 -0,00278 -24,6 0,001 236,506 19.11.22 4:40 0 empty
9 1733 -0,00235 -24,4 -0,083 236,510 19.11.22 4:45 0
9 1733 -0,00144 -23,4 0,027 236,569 19.11.22 6:10 0
9 1733 -0,00104 -23,0 -6,535* 236,585 19.11.22 6:33 18
9 1733 -0,00095 -22,9 1,787* 236,589 19.11.22 6:39 16
8 1767 0,00422 -15,6 0,034 238,438 21.11.22 2:36 0
7 1800 -0,00061 -18,6 0,024 238,978 21.11.22 15:27 1
*these fM(fNP) values are very uncertain
2023
5 1833 -0,00523 99,8 -0,006 236,039 18.11.23 23:42 0 empty
5 1833 -0,00524 99,8 0,002 236,039 18.11.23 23:42 0 empty
5 1833 -0,00502 98,8 0,070 236,054 19.11.23 0:04 0
9 1733 0,00248 -16,2 0,004 237,451 20.11.22 9:18 0 empty
9 1733 0,00249 -16,2 -0,002 237,463 20.11.22 9:36 0 empty
9 1733 0,00232 -15,7 0,003 237,566 20.11.22 12:03 0 empty
9 1733 0,00215 -14,6 -0,004 237,759 20.11.22 16:38 0 empty
9 1733 0,00207 -14,6 0,020 237,760 20.11.22 16:39 2
9 1733 0,00194 -14,7 -0,055 237,763 20.11.22 16:43 6
9 1733 0,00217 -14,6 0,004 237,765 20.11.22 16:47 0 empty
8 1767 0,00021 -15,0 0,005 238,569 21.11.22 11:53 1 empty
8 1767 0,00014 -15,0 -0,009 238,569 21.11.22 11:53 3 empty
8 1767 0,00054 -15,0 0,035 238,572 21.11.22 11:58 9
7 1800 -0,00530 -18,3 0,021 238,916 21.11.23 20:08 0
2024
4 1899 -0,00595 -39,4 0,423 235,610 17.11.24 19:39 0
5 1833 -0,00574 100,0 -0,043 235,965 18.11.24 4:07 0
5 1833 -0,00608 99,9 0,001 235,978 18.11.24 4:24 0 empty
3 1932 0,00259 -46,3 0,440 236,116 18.11.24 7:43 2
9 1733 -0,00172 -14,5 0,004 237,802 19.11.24 23:48 1 empty
9 1733 -0,00190 -14,3 -0,103 237,824 20.11.24 0:19 15
9 1733 -0,00202 -14,1 0,159 237,842 20.11.24 0:46 23
8 1767 -0,00555 -14,4 0,028 238,320 20.11.24 12:07 0
2025
10 1699 0,00015 -19,5 0,062 235,323 17.11.25 18:59 1
10 1699 0,00020 -19,4 -0,172 235,327 17.11.25 19:06 3
10 1699 -0,00177 -21,7 -0,346 235,349 17.11.25 19:36 2
10 1699 -0,00184 -21,8 0,252 235,351 17.11.25 19:39 2
10 1699 -0,00121 -18,2 0,002 235,438 17.11.25 21:44 0 empty
10 1699 -0,00063 -17,3 -0,448 235,490 17.11.25 22:58 18
5 1866 0,00329 -28,6 -0,021 235,651 18.11.25 2:47 0
5 1866 0,00333 -28,7 0,002 235,650 18.11.25 2:46 0 empty
5 1866 0,00397 -26,0 0,556 235,763 18.11.25 5:27 1
10 1699 -0,00054 -14,0 0,001 235,829 18.11.25 7:01 0 empty
10 1699 -0,00064 -13,6 0,001 235,829 18.11.25 7:01 1 empty
10 1699 -0,00028 -13,7 -0,001 235,837 18.11.25 7:14 1 empty
4 1899 -0,00149 -31,6 0,332 236,437 19.11.25 21:29 2
3 1932 -0,00246 -39,4 0,112 237,143 19.11.25 14:17 0
2026
10 1666 0,00655 36,8 -0,227 232,908 15.11.26 15:38 0
10 1666 0,00351 40,3 0,052 233,492 16.11.26 5:33 0
10 1699 -0,00399 -9,1 0,000 236,292 19.11.26 0:12 0 empty
10 1699 -0,00247 -9,7 0,010 236,394 19.11.26 2:37 4
10 1699 -0,00246 -9,2 -0,005 236,447 19.11.26 3:53 2
10 1699 -0,00244 -9,2 0,024 236,448 19.11.26 3:55 9
10 1699 -0,00243 -9,2 -0,090 236,462 19.11.26 4:15 35
6 1833 -0,00389 -18,1 0,000 236,537 19.11.26 6:01 0 empty
6 1833 -0,00440 -19,3 0,001 236,936 19.11.26 16:27 0 empty
13 1600 0,00175 -6,3 0,028 236,991 19.11.26 16:49 19
6 1833 -0,00456 -20,1 0,241 237,037 19.11.26 17:55 0
6 1833 -0,00402 -19,4 -0,019 237,059 19.11.26 18:26 0
6 1833 -0,00352 -18,1 -0,004 237,062 19.11.26 18:31 0
5 1866 -0,00545 -20,6 0,112 237,320 20.11.26 0:40 0
7 1800 -0,00567 -14,9 0,101 237,412 20.11.26 2:50 1
8 1767 -0,00582 -12,3 0,074 237,521 20.11.26 5:27 2
2027
13 1600 -0,00341 -5,1 -0,003 236,886 19.11.27 20:29 0 empty
13 1600 -0,00025 -5,1 0,002 236,972 19.11.27 22:31 10empty
13 1600 -0,00035 -5,1 -0,005 236,987 19.11.27 22:53 23empty
13 1600 -0,00062 -5,0 -0,008 236,991 19.11.27 22:59 24empty
13 1600 -0,00048 -5,1 0,005 237,008 19.11.27 23:23 19empty
13 1600 -0,00007 -4,5 0,000 237,231 20.11.27 4:41 2 empty
13 1600 -0,00063 -4,5 0,000 237,335 20.11.27 7:08 1 empty
13 1600 -0,00091 -4,5 -0,014 237,472 20.11.27 10:24 24
2028
No encounters found
2029
No encounters found
2030
No encounters found
Best regards, Mikhail Maslov
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