Asteroid 2017 RS - an extinct comet?

Asteroid 2017 RS was first observed at Pan-STARRS 1, Haleakala on 2017-09-01. 

It is classified as a Mars-crosser.

Its orbit is still very uncertain (condition code 9).

It would be nice to have more data because this asteroid may be an extinct comet.

Orbital data

From JPL Small-Body Database Browser we can see:

(2017 RS)

Classification: Outer Main-belt Asteroid          SPK-ID: 3781340

[ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters ]

[ show orbit diagram ]

Orbital Elements at Epoch 2457998.5 (2017-Sep-02.0) TDB Reference: JPL 1 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .6145637063005263 0.020702 a 4.14837857496493 0.18924 au q 1.598935662796787 0.016606 au i 16.490996995339 0.23653 deg node 221.6460003522266 0.96443 deg peri 165.4311035552846 2.8664 deg M 351.0338219139737 0.34606 deg tp 2458075.363624646766 (2017-Nov-17.86362465) 2.4617 JED period 3086.142680565361 8.45 211.17 0.5782 d yr n .1166504718874665 0.0079819 deg/d Q 6.697821487133073 0.30553 au

Orbit Determination Parameters    # obs. used (total)      18      data-arc span      5 days      first obs. used      2017-09-01      last obs. used      2017-09-06      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      9      fit RMS      .20988      data source      ORB      producer      Otto Matic      solution date      2017-Sep-06 18:12:03   Additional Information  Earth MOID = .609695 au   Jupiter MOID = .352027 au   T_jup = 2.605

Simulation in the past 

I used Mercury6 simulator by John Chambers to check what might have happened in the last 10^8 days (about 273000 years).

The arbitrary threshold for the ejection distance is 100 AU.

           Integration parameters
           ----------------------

   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:                0.050 days
   Accuracy parameter:              1.0000E-12
   Central mass:                    1.0000E+00 solar masses
   J_2:                              0.0000E+00
   J_4:                              0.0000E+00
   J_6:                              0.0000E+00
   Ejection distance:               1.0000E+02 AU
   Radius of central body:          5.0000E-03 AU

I generated 100 clones with a little R script.

Every orbital parmeter has an average similar to the correspondent nominal one.

Every orbital parameter has a standard deviation equal to the uncertainty shown above.

Result of the simulation for the nominal orbit

These graphs were made using the R ggplot package.

Result of the simulation with 100 clones

After the simulation, I got 78 out of 100 clones that arrived from the outskirt of the solar system.

The actual arrival date range is extremely high: the most recent date was about 1565 AD.

The arrival date distribution is like this (time here is expressed in years):

Kind Regards,

Alessandro Odasso

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