2017 QO32 versus NEO P10COCz

Peter Birtwhistle noticed a similarity between the orbits of these two newly discovered asteroids (see his MPML message).

I tried to simulate, using the Mercury integrator by John E. Chambers, their past relative distance and velocity.

The data are still very uncertain and so this simulation is by no means conclusive: however, it seems that in these days these two asteroids are at the end of a much longer cycle where they happen to come relatively near.

When more data are available, it will be interesting to see if there is a point in the past when the distance between these two asteroids was much less than a lunar distance and their relative velocity was less than say 1 m/s.

Simulation data

Today, 30 Aug 2017, I downloaded the observations  made available by the Minor Planet Center, then I got the orbital parameters submitting them to Find_Orb (server page).

Simulation configuration




From file info.out:
   Algorithm: Bulirsch-Stoer (conservative systems)

   Integration start epoch:       2458000.5000000 days
   Integration stop  epoch:      -100000000.0000000
   Output interval:                  100.000
   Output precision:                 medium

   Initial timestep:                0.100 days
   Accuracy parameter:              1.0000E-12

Simulation result

Note: the apparent zero points both in relative distance and velocity are NOT really zero! 


Kind Regards,
Alessandro Odasso

Hilda Asteroid 2017 OJ65 - an old TNO?

This object is currently an Hilda asteroid.

I run a simulation using the nominal orbital parameters read from JPL (Horizons Web Interface).

Uncertainty condition code: 0

Mercury6 simulator: configuration

More about the orbit simulator "A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies'' can be found here.

Main integration parameters:

   Algorithm: Bulirsch-Stoer (conservative systems)

   Integration start epoch:         2458000.5000000 days
   Integration stop  epoch:        -10^8 days
   Output interval:                     100.000 days
   Output precision:                   medium
   Initial timestep:                      0.100 days
   Accuracy parameter:             1.0000E-12
   Ejection distance:                  1.0000E+02 AU

Simulation results

This plot has been made using the R-package.

This seems to show that this asteroid was previously a TNO.

Kind Regards,
Alessandro Odasso

Asteroid 2017 DQ15

Asteroid 2017 DQ15 is a NEO (Apollo) displayed in the list of objects with a comet-like orbit maintained by Y. Fernandez.

Orbital Elements at Epoch 2458000.5 (2017-Sep-04.0) TDB
Reference: JPL 7 (heliocentric ecliptic J2000)

Element Value Uncertainty (1-sigma)   Units  e .7272164269790051 1.279e-05 a 2.823784780342436 0.00011852 au q .7702821018241148 3.8782e-06 au i 20.18557131636563 0.00017551 deg node 272.8777420846461 0.00046785 deg peri 350.4179039106148 0.00040687 deg M 22.44168793940112 0.0013623 deg tp 2457892.456452631231 (2017-May-18.95645263) 0.00026204 JED period 1733.18857109974 4.75 0.10912 0.0002988 d yr n .207709654911683 1.3077e-05 deg/d Q 4.877287458860757 0.00020471 au

Orbit Determination Parameters    # obs. used (total)      43      data-arc span      187 days      first obs. used      2017-02-10      last obs. used      2017-08-16      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      5      fit RMS      .50315      data source      ORB      producer      Otto Matic      solution date      2017-Aug-17 06:19:02   Additional Information  Earth MOID = .22774 au   Jupiter MOID = .339108 au   T_jup = 2.792

Based on the nominal orbital parameters and uncertainty, I generated 100 clones with an R script and then I used the Mercury6 simulator by J.E. Chambers to investigate what happened in the last 10^8 days.

Mercury6 simulator: configuration

More about the program "A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies'' can be found here.

Main integration parameters:

   Algorithm: Bulirsch-Stoer (conservative systems)

   Integration start epoch:         2458000.5000000 days
   Integration stop  epoch:        -10^8 days
   Output interval:                     100.000 days
   Output precision:                   medium
   Initial timestep:                      0.100 days
   Accuracy parameter:             1.0000E-12
   Ejection distance:                  1.0000E+02 AU

Simulation results

As seen above, the "ejection distance" used to claim that an asteroid has arrived from the outskirts of the solar system is 100 AU.

The simulation shows that there is a good likelyhood that the asteroid has a cometary origin:

• 47 out of 100 clones arrived from a distance greater than 100 AU in the last 10^8 days
• 4 out of 100 clones would have "collided" with the sun 

The most recent arrival time was about 7906 B.C.

The mean arrival time was about 139274 B.C.

The less recent arrival time was about 268318 B.C.

The arrival time distribution of the 47 clones that were likely to be comets is shown below:

Kind Regards,

Alessandro Odasso