Amors: (2019 QR6) and (2019 PR2)

On October 06th, 2019 I post a message on MPML list wondering about the nature of these two objects.

In fact that I was unable to link their orbits with Find_Orb. 

The message  was almost immediately answered by Bill Gray that already noticed the orbit similarity as you see in his answer.

For what is's worth, I tried a simulation going back just a few centuries.

I used the Mercury6 simulator (Bulirsch-Stoer algorithm, output every 100 days) to integrate the orbit of 100 clones for every Amor.

package by J.E.Chambers (1999) ``A Hybrid
      Symplectic Integrator that Permits Close Encounters between
      Massive Bodies''. Monthly Notices of the Royal Astronomical
      Society, vol 304, pp793-799.

[ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

[ show orbit diagram ]

Orbital Elements at Epoch 2458600.5 (2019-Apr-27.0) TDB Reference: JPL 6 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .7978288096308341 0.00032564 a 5.77647017220784 0.0096039 au q 1.16783585084724 6.0685e-05 au i 10.97219839923067 0.0022769 deg node 349.0031380596452 0.0032242 deg peri 57.11459122817678 0.0037867 deg M 347.1017843073122 0.032425 deg tp 2458782.185121653621 (2019-Oct-25.68512165) 0.0037127 TDB period 5070.983875109436 13.88 12.646 0.03462 d yr n .07099214055225742 0.00017705 deg/d Q 10.38510449356844 0.017266 au

Orbit Determination Parameters    # obs. used (total)      55      data-arc span      37 days      first obs. used      2019-08-30      last obs. used      2019-10-06      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      6      norm. resid. RMS      .23771      source      ORB      producer      Otto Matic      solution date      2019-Oct-06 05:59:04   Additional Information  Earth MOID = .236027 au   Jupiter MOID = .430677 au   T_jup = 2.148

(2019 QR6)

Classification: Amor [NEO]          SPK-ID: 3843716

[ Ephemeris | Orbit Diagram | Orbital Elements | Mission Design | Physical Parameters | Close-Approach Data ]

[ show orbit diagram ]

Orbital Elements at Epoch 2458600.5 (2019-Apr-27.0) TDB Reference: JPL 13 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .7976395056810581 7.5679e-05 a 5.771314015088342 0.0022317 au q 1.167885956963114 1.4922e-05 au i 10.98927716153723 0.0004847 deg node 349.0377844945419 0.00064504 deg peri 57.08297761694006 0.0010614 deg M 347.0982101299367 0.0075621 deg tp 2458781.992192675281 (2019-Oct-25.49219268) 0.0011319 TDB period 5064.195745018806 13.87 2.9374 0.008042 d yr n .0710872995685642 4.1233e-05 deg/d Q 10.37474207321357 0.0040118 au

Orbit Determination Parameters    # obs. used (total)      79      data-arc span      56 days      first obs. used      2019-08-10      last obs. used      2019-10-05      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      5      norm. resid. RMS      .47936      source      ORB      producer      Otto Matic      solution date      2019-Oct-06 05:59:04   Additional Information  Earth MOID = .236151 au   Jupiter MOID = .430922 au   T_jup = 2.149

(2019 PR2)

Classification: Amor [NEO]          SPK-ID: 3843547

I generated the clones trying to achieve the same orbital values as above.
This is what I got:

2019 QR6 

	Clones			Target
	mean	sd		mean	sd
q	1.16782936	6.072e-05		1.16783585	6.068e-05
e	0.7977961	0.00032594		0.79782881	0.00032564
i	10.97196669	0.00227869		10.9721984	0.0022769
peri	57.11505214	0.00378487		57.11459123	0.0037867
node	349.00281358	0.00322763		349.00313806	0.0032242
tp	2458782.18556559	0.00370968		2458782.18512165	0.0037127

2019 PR2

	Clones			Target
	mean	sd		mean	sd
q	1.16788572	1.491e-05		1.16788596	1.492e-05
e	0.79763725	7.562e-05		0.79763951	7.568e-05
i	10.98925764	0.00048534		10.98927716	0.0004847
peri	57.08297444	0.00106018		57.08297762	0.0010614
node	349.03776263	0.00064461		349.03778449	0.00064504
tp	2458781.99219263	0.00113238		2458781.99219268	0.0011319

I analyzed the 100*100 pairs, looking for pairs being very near with low relative velocity.

The best couple that I found behaved like this:

Apparently, somewhere around  year 1950 these two asteroids were at 2500 km with a relative velocity abot 10 m/s.

Does this make any sense?

Kind Regards
Alessandro Odasso