C/2014 OG392 - about its cometary origin

A coma was recently detected as far as 400,000 km from centaur 2014 OG392 by NAU researchers (click here to access their paper).

Following this discovery, the centaur was given a comet designation: C/2014 OG392 

C/2014 OG392 (PANSTARRS)

Classification: Chiron-type Comet          SPK-ID: 1003735

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

[ show orbit diagram ]

Orbital Elements at Epoch 2457785.5 (2017-Feb-01.0) TDB Reference: JPL 14 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .1804389828275273 7.4417e-06   a 12.150254615787 0.00018697 au q 9.957875031818922 6.704e-05 au i 9.046144236347711 4.6644e-05 deg node 145.8645384329216 0.00015579 deg peri 254.7881434680575 0.0027215 deg M 318.4435044274125 0.0027357 deg tp 2459571.218143409214 (2021-Dec-22.71814341) 0.076746 TDB period 15469.50778138701 42.35 0.35708 0.0009776 d yr n .0232715872468259 5.3717e-07 deg/d Q 14.34263419975507 0.00022071 au

Orbit Determination Parameters    # obs. used (total)      213      data-arc span      3371 days (9.23 yr)      first obs. used      2011-07-27      last obs. used      2020-10-18      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      3      norm. resid. RMS      .22122      source      ORB      producer      Otto Matic      solution date      2020-Oct-26 19:43:48   Additional Information  Earth MOID = 8.97742 au   Jupiter MOID = 5.06363 au   T_jup = 3.397

I tried to investigate the cometary nature running a backward integration using Mercury6 software by E. Chambers.

I generated 100 clones trying to achieve the same nominal orbital parameters and uncertainty as above.

	Clones			Target
	mean	sd		mean	sd
q	9.95787410878	6.694624e-05		9.95787503182	6.704e-05
e	0.18043892764	7.50991e-06		0.18043898283	7.4417e-06
i	9.04614599334	4.699782e-05		9.04614423635	4.6644e-05
peri	254.78819470552	0.00271470415		254.78814346806	0.0027215
node	145.86454031167	0.0001548109		145.86453843292	0.00015579
tp	2459571.21974672	0.07635106812		2459571.21814341	0.076746

Simulation parameters

integration algorithm: Bulirsch-Stoer

ejection distance from the solar system: 100 au

simulation start time: 2020 A.D.

simulation stop time: -1d8 (about -274K years BC)

Simulation results

A "true" cometary origin is confirmed for 29 clones, in fact, they entered the solar system from a distance greater than 100 au according to this arrival time distribution

In order to read the following plots, you need to know that:

the simulated time is divided into 50 intervals , in every interval and for every clone I have calculated the min perihelium and then I have plotted the interquantile distribution in that interval.

Similar approach for max aphelium, max eccentricity, ... etc.

Perihelium q

Aphelium Q

Eccentricity e

Inclination i

Peri w

Node om

Kind Regards,

Alessandro Odasso

Centaur 2020 MK4

 See Sam Deen's post on MPML

JPL Small-Body Database Browser

(2020 MK4)

Classification: Centaur          SPK-ID: 54028098

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

[ show orbit diagram ]

Orbital Elements at Epoch 2459000.5 (2020-May-31.0) TDB Reference: JPL 4 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .02195188337952747 0.00026496   a 6.158612875846196 0.00097828 au q 6.023419724215964 0.0020101 au i 6.667359451314571 0.00055296 deg node 2.340270538083764 0.0080184 deg peri 176.0179742158394 0.82761 deg M 112.9081690495819 0.85696 deg tp 2457249.663268073103 (2015-Aug-15.16326807) 12.903 TDB period 5582.423564205491 15.28 1.3301 0.003642 d yr n .06448811987472979 1.5366e-05 deg/d Q 6.293806027476427 0.00099976 au

Orbit Determination Parameters    # obs. used (total)      99      data-arc span      70 days      first obs. used      2020-06-15      last obs. used      2020-08-24      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      5      norm. resid. RMS      .42831      source      ORB      producer      Otto Matic      solution date      2020-Sep-07 09:41:28   Additional Information  Earth MOID = 5.02655 au   Jupiter MOID = .574557 au   T_jup = 3.006

Backward simulation 

100 clones generated:

	Clones			Target
	mean	sd		mean	sd
q	6.02351360763	0.00201082117		6.02341972422	0.0020101
e	0.02194045805	0.00026498393		0.02195188338	0.00026496
i	6.66737828519	0.00055323416		6.66735945131	0.00055296
peri	176.0244406455	0.82839257994		176.01797421584	0.82761
node	2.33984409116	0.00803481217		2.34027053808	0.0080184
tp	2457249.73101293	12.90996695426		2457249.66326807	12.903

The simulation was performed with Mercury6 simulator from J. E. Chambers.

The time interval from now back to 180K years ago was investigated.

The following clones appear yo have a cometary origin because they entered the solar system from a distance greater than 100 AU:

 MK87     ejected at      -3992 10 15.95739

 MK25     ejected at     -11386  5  6.63099

 MK69     ejected at     -11668  7 18.91268

 MK65     ejected at     -13267  1  2.82563

 MK66     ejected at     -13674  4 27.93527

 MK57     ejected at     -18216 12  4.27966

 MK16     ejected at     -22393 11 16.92234

 MK56     ejected at     -24538  5 23.00058

 MK100    ejected at     -24872 11  3.71037

 MK33     ejected at     -25672  8 29.33118

 MK14     ejected at     -26908 10 12.16609

 MK79     ejected at     -27042  1 10.47236

 MK59     ejected at     -27477  5 21.28744

 MK41     ejected at     -28193 12 31.77309

 MK50     ejected at     -28229  6 24.30764

 MK70     ejected at     -30832  2 18.82571

 MK86     ejected at     -33366 10  3.35722

 MK83     ejected at     -36505  4 22.99516

 MK11     ejected at     -42971  5 25.41050

 MK52     ejected at     -43914  6 24.36384

 MK15     ejected at     -45152 10 31.83684

 MK75     ejected at     -46261  3 18.78421

 MK20     ejected at     -46400  2 13.00000

 MK24     ejected at     -52981  8  4.81971

 MK39     ejected at     -54008  2  8.41040

 MK44     ejected at     -54032  5 23.55889

 MK36     ejected at     -56218  3  9.00000

 MK13     ejected at     -58238  6 27.08479

 MK58     ejected at     -61702  8 22.73425

 MK73     ejected at     -63075  1 20.75482

 MK63     ejected at     -65472  1 22.91155

 MK98     ejected at     -69333 10 24.33742

 MK19     ejected at     -70475  6 20.82479

 MK43     ejected at     -76905  9 26.09250

 MK78     ejected at     -81576  4 16.15310

 MK5      ejected at     -81766  3 24.20996

 MK27     ejected at     -81906  2 20.04496

 MK88     ejected at     -82300 11  9.76100

 MK84     ejected at     -82695  7 11.00000

 MK53     ejected at     -83313  4 14.51728

 MK64     ejected at     -85820  2 27.87065

 MK51     ejected at     -86401  8 29.32042

 MK7      ejected at     -90081  6 21.71342

 MK61     ejected at     -94034  3 26.84777

 MK10     ejected at     -95133 10 16.26793

 MK92     ejected at     -96254  6 24.13705

 MK68     ejected at     -97012  6 11.67088

 MK21     ejected at     -97348  9 22.80596

 MK34     ejected at     -97977  4  4.52762

 MK90     ejected at    -105289  3  9.80638

 MK32     ejected at    -107468  8 18.14496

 MK3      ejected at    -110733 12 20.80791

 MK40     ejected at    -113571 10  4.91780

 MK76     ejected at    -116794  4 30.66382

 MK38     ejected at    -122623  3 31.58393

 MK8      ejected at    -123524  2 13.51981

 MK80     ejected at    -124886  5  8.57397

 MK9      ejected at    -141230 12 15.21267

 MK91     ejected at    -142117  5 23.59862

 MK97     ejected at    -151011  6 25.85088

 MK82     ejected at    -158864 10 19.14006

 MK81     ejected at    -160420  4 20.25107

  was hit by MK17     at    -168177  7  5.2

 MK31     ejected at    -176722 11  5.97609

Cheers,

Alessandro Odasso

174P/Echeclus

60558 Echeclus (2000 EC98) also known as 174P/Echeclus is a centaur that occasionally shows a cometary activity.

Outbursts happened in 2005, 2011 and in the first days of December 2017 (see MPML message from Brian Skiff) and confirmation from Richard Miles and Jean-François Soulier.

The 2017 outburst is the strongest ever witnessed.

I simulated 100 clones of this centaur in the past 10^8 days trying to confirm its possible cometary origin: note that I am not taking into account the non gravitational forces associated to its outburst, not clear to me if they have a considerable effect.

The first step was to generate clones having orbital parameters distributed around the nominal ones with 1-sigma uncertainty as follows:

JPL Small-Body Database Browser

60558 Echeclus (2000 EC98)

Classification: Centaur          SPK-ID: 2060558

[ Ephemeris | Orbit Diagram | Orbital Elements | Physical Parameters | Discovery Circumstances | Close-Approach Data ]

[ show orbit diagram ]

Orbital Elements at Epoch 2458000.5 (2017-Sep-04.0) TDB Reference: JPL 85 (heliocentric ecliptic J2000)  Element Value Uncertainty (1-sigma)   Units  e .4556668817376728 1.2005e-07 a 10.68172886788859 2.2774e-06 au q 5.814418783090517 4.1275e-07 au i 4.344445692331014 6.4394e-06 deg node 173.3332131350017 5.505e-05 deg peri 162.8042218299513 5.7268e-05 deg M 24.47205469604485 6.4974e-06 deg tp 2457133.680473384613 (2015-Apr-21.18047338) 0.00022632 JED period 12751.48464064088 34.91 0.004078 1.116e-05 d yr n .02823200671493785 9.0289e-09 deg/d Q 15.54903895268667 3.3152e-06 au

Orbit Determination Parameters    # obs. used (total)      2888      data-arc span      13948 days (38.19 yr)      first obs. used      1979-09-23      last obs. used      2017-11-30      planetary ephem.      DE431      SB-pert. ephem.      SB431-N16      condition code      0      fit RMS      .44363      data source      ORB      producer      Otto Matic      solution date      2017-Dec-07 16:00:47   Additional Information  Earth MOID = 4.80483 au   Jupiter MOID = .838614 au   T_jup = 3.031

Simulation approach

Mercury6 Integrator

reference:

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.

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

   Algorithm: Bulirsch-Stoer (general)

   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


Simulation Results

• 77 out of 100 clones have a cometary orbit (i.e. they came from a distance greater than 100 AU).

• of which: 3 came on a hyperbolic orbit. The one that had the highest speed had a Vinfinity about 3.7 km/s (Vinfinity = 42.1219*sqrt(-0.5/a) --> the semi-major axis being about -63.6 AU

The time (Year) when they entered the solar system was distributed as follows:

   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
-272080 -109330  -62183  -82802  -36357   -4980

In a graphical form:

A look at the nominal asteroid
The nominal asteroid itself has a cometary origin.

It entered into the solar system at about year -105000 B.C.

In the plot below, the dashed vertical lines correspond to a close approach with Jupiter.

Note that Jupiter was not immediately important. 

In its early history, 174P/Echeclus was much more influenced by Saturn as shown here:

Coming back to plots showing the role of Jupiter, we can see these other ones:

A look at the clones - "footprint" diagrams

At any given time in the past, a clone had a certain perihelium q and a certain aphelium Q (I disregard the clones when on an hyperbolic trajectory because Q would be infinite).

Let's imagine that we plot all possible q-Q points in a diagram: the highest density area is the one where the clones happened to be for most of the time.

This is shown here ( I have used the R function stat_density2d - color scale implemented by viridis library):

Analysis of close approaches
These plots show the distribution of close appproaches (number and Dmin distance) between the clones and the major planets.

Kind Regards,
Alessandro Odasso