(395103) = 2009 RA8 -- Cometary Origin ?

 Is this a quasi-Hilda object?

Clone Generation

100 clones were generated in order to have the same orbital paameters and uncertainty as the nominal asteroid

	Clones			Target
	mean	sd		mean	sd
q	3.61245270083945	3.39064109921033e-07		3.61245264912673	3.4136e-07
e	0.129667339794439	8.11352970562344e-08		0.12966735411561	8.0309e-08
i	8.9645643748396	9.73657795759391e-06		8.96456457281582	9.6087e-06
peri	344.487704195712	4.69757841212335e-05		344.487707120445	4.6654e-05
node	359.469501444993	3.82226393976073e-05		359.469498781976	3.8729e-05
tp	2461090.03289397	0.000262107424207425		2461090.03290289	0.00026503

Backward Simulation

This was performed using Mercury Integrator Package Version 6 - Bulirsch-Stoer N-body algorithm - 10^8 days in the past - output every 100 days

66% of the clones entered the solar system from a distance greater than 100 AU (i.e. from the point of view of the backward simulation they were "ejected")

Asteroid 2006 XL5 - likely cometary origin

The orbits of asteroid 2006 XL5 and comet 75D/Kohoutek are vaguely similar:

                        a         e        i       om        w       q
       (2006 XL5) 3.723259 0.5154009 4.526352 274.0060 175.1221   1.804288
   75D/Kohoutek   3.543147 0.4963074 5.907209 269.6861 175.8017   1.784657

It is not clear to me if asteroid 2006 XL5 with a diameter about 1.6 km might be an old fragment of the lost comet that was estimated to be about 4.6 km in diameter.

I tried a backward simulation but there is no clear indication that this is the case.

What is interesting is that 2006 XL5 might have a cometary origin itself (the MOID with jupiter is about 0.16 AU).

Clones generation

I generated 100 clones of asteroid 2006 XL5 trying to achieve the same mean orbital parameters (and uncertainty).

	Clones			2006 XL5
	mean	sd		mean	sd
q	1.80428798284277	5.24177295141045e-07		1.80428796355464	5.2592e-07
e	0.515400864913161	1.29060036714178e-07		0.515400869129902	1.2918e-07
i	4.52635127581998	7.48101264185302e-06		4.52635163398884	7.4744e-06
peri	175.122110003296	0.000109392746353213		175.122116165405	0.00010898
node	274.006039830699	9.87233639993821e-05		274.006030101048	9.8249e-05
tp	2459319.93402565	0.000249555965707767		2459319.93400848	0.00024939

 

Backward simulation config parameters

Mercury6 software - package version 6 by John E. Chambers

)O+_06 Integration parameters  (WARNING: Do not delete this line!!)
) Lines beginning with `)' are ignored.
)---------------------------------------------------------------------
) Important integration parameters:
)---------------------------------------------------------------------
 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS
 start time (days)= 2459806.5
 stop time (days) = -1d8
 output interval (days) = 100
 timestep (days) = 0.05
 accuracy parameter=1.d-12
...

 ejection distance (AU)= 100

based on this configuration, any clone coming into the solar system from a distance greater than 100 AU is considered to have a "cometary origin".

Simulation results

75% of the clones have a cometary origin

 ddd

2021 CC40 - cometary origin ?

Its orbit has a Jupiter moid = 0.0060 AU

I generated 100 clones of 2021 CC40 in the last 10^8 days (i.e. from now back to about 280K years ago).
75 clones came into the solar system from a distance greater than 100 AU

From this point of view, it seems that 2021 CC40 is a good candidate for having a cometary origin.

 

More details here:

 

Clones Generation

	Clones			Target
	mean	sd		mean	sd
q	3.25399802390041	7.03707449970568e-05		3.25400084057019	7.0403e-05
e	0.241134331789963	1.59398555200895e-05		0.241133698559336	1.5947e-05
i	12.9796232392302	6.18646863798976e-05		12.9796210051976	6.1886e-05
peri	328.501490543462	0.00855370237432572		328.501160286746	0.008554
node	235.614402285421	0.000361242956610133		235.61440679467	0.00036124
tp	2459672.09000109	0.0444299088063099		2459672.08824673	0.044429

Mercury6 Simulation

)O+_06 Integration parameters  (WARNING: Do not delete this line!!)
) Lines beginning with `)' are ignored.
)---------------------------------------------------------------------
) Important integration parameters:
)---------------------------------------------------------------------
 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = BS
 start time (days)= 2459671.5
) stop time (days) = 102458000.5
 stop time (days) = -1d8
 output interval (days) = 100
 timestep (days) = 0.05
 accuracy parameter=1.d-12

...

 ejection distance (AU)= 100
 

Results

In the following plots, time is displayed on the vertical axis in order to have more space. The simulation time has been divided into 50 slots and for every slot the relevant orbital parameter distribution (inter-quartile) of all existing clones is shown.

2016 PG215 vs P/2017 S9 (PANSTARRS)

Tony Dunn's simulator

After importing these two objects in Tony Dunn's orbit simulator, I run a backward simulation, it seems that these two objects reached their minimum distance (about 1.3 million km with a relative velocity about 0.2 km/s) around year 1722

 

I tried to repeat the simulation with Mercury6

Mercury 6 - Clone Generation

100 clones generated for 2016 PG215

	Clones			Target
	mean	sd		mean	sd
q	2.19383272749	0.00011273758		2.19381712	0.000112
e	0.30458368136	6.94602e-05		0.3045753	6.89e-05
i	14.48177635302	0.00100947136		14.48182	0.001
peri	239.08631656434	0.02910871896		239.08509	0.029
node	143.95467584065	0.00332139145		143.95526	0.0033
tp	2457678.38420939	0.0801469034		2457678.38108	0.0813

 

100 clones generated for P/2017 S9 (PANSTARRS)

	Clones			Target
	mean	sd		mean	sd
q	2.19533547065	0.00016184005		2.19530577	0.000163
e	0.30464978716	0.00044947392		0.3046144	0.00045
i	14.13853528807	0.00079956654		14.1385	8e-04
peri	237.90055621894	0.04184388237		237.90083	0.042
node	146.22097511564	0.01186594777		146.22069	0.012
tp	2457958.09135804	0.08433898023		2457958.07442	0.0837

Mercury6 - Simulation parameters

algorithm: BS

output intervals: 10 days

timestep=0.05 days

Mercury6 - Simulation Results

I compared the resulting 10000 clone couples.

Looking at minimum distance, the two best clones behaved like this:

Looking at the mimimum relative velocity, the other two best clones behaved like this:

Clearly, due to the orbit uncertainties, we have a high variance in distance, speed and time, but I wonder whether we can reasonably speculate that the asteroid 2016 PG215 is a fragment of comet P/2017 S9 (PANSTARRS) or whether this is just something occurring by chance.

 

Best wishes,

Alessandro Odasso