In an interesting MPML message, Sam Deen who found precovery images of this comet has shown that P/2020 F1 Leonard had a close encounter with Saturn in May 1936.
The close approach has been confirmed by Denis Denisenko and also by Syuichi Nakano that mentioned it in CBET 4737 (see by Brian Skiff's note ).
Denis Denisenko has also shown that what was previously thought to be a galaxy known as SDSS J113712.61+064629.0 was in fact the same comet!
It seems that the close approach with Saturn occurred at less than 1 mln km distance, quoting his words "coming to the point where Titan should be probably taken into account".
Due to this possibility, I am not sure if the below simulation can be reliable because even if all planets (including Uranus and ... well ... also former planet Pluto) were taken into account, I did not add Titan.
As suggested by Denis Denisenko, Titan should probably be taken into account because according to the simulation results shown below, the close encounter with Saturn could have occurred at a distance much much lower than 1 mln km... I really wonder if what shown below makes sense!.
I generated 100 clones trying to achieve the same orbital parameters reported in JPL Small-Body Database.
| [ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ] |
[ show orbit diagram ]
| Orbital Elements at Epoch 2458881.5 (2020-Feb-02.0) TDB Reference: JPL 1 (heliocentric ecliptic J2000)
| Orbit Determination Parameters
Additional Information
|
| P/2020 F1 (Leonard) |
| Classification: Jupiter-family Comet SPK-ID: 1003664 |
Clones simulated
| Clones | Target | ||||
|---|---|---|---|---|---|
| mean | sd | mean | sd | ||
| q | 3.98312397488 | 3.011474e-05 | 3.9831186562 | 3.0111e-05 | |
| e | 0.41673463882 | 3.223462e-05 | 0.41672941378 | 3.2093e-05 | |
| i | 5.43588826127 | 9.318419e-05 | 5.43588701249 | 9.3305e-05 | |
| peri | 8.69166111114 | 0.00503993969 | 8.6921440959 | 0.0050162 | |
| node | 136.65698385154 | 0.00067172871 | 136.65704253563 | 0.0006689 | |
| tp | 2458724.74745393 | 0.03690546666 | 2458724.75149385 | 0.036878 | |
Simulation Details
Mercury6 simulator by John E. Chambers.
)---------------------------------------------------------------------
) Important integration parameters:
)---------------------------------------------------------------------
algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS
start time (days)= 2459000.5
stop time (days) = -1d8
output interval (days) = 100
timestep (days) = 0.05
accuracy parameter=1.d-12
Simulation Results
The comet P/2020 F1 Leonard - taking into account its nominal params, seems to have entered the solar system (conventional distance 100 AU) about 45K years ago while the first clones did it even earlier about 10-20K years ago.
Considering the close encounter with Saturn:
- the "nominal" comet had the encounter on May 12, 1936 (distance 0.0046 AU - about 700000 km). Note that the simulation step was 0.05 days, I wonder if this "granularity" may explain the difference compared with the real nominal distance that was achieved on May 7th/8th.
( telnet horizons.jpl.nasa.gov 6775 ), a similar date is found:
Close-approach results:
Time (JDTDB): 2428300.80754
Date (TDB): 1936 May 12.30754
Body: Satrn
CA Dist : .004603
MinDist : .000000
MaxDist: .022999
Vrel: 10.676- more in general, 99 clones (including the nominal comet) had the close encounter with Saturn in 1936, the other one had it in 1937.
Can the simulator manage such a situation?
Not clear to me ... however, out of curiosity, let's say for a moment ... yes!
In the following plots we can clearly see the "orbital disruption" suffered by the comet when it passed near Saturn in the 1930's.
Kind Regards,
Alessandro Odasso
