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Showing posts with label cometary origin. Show all posts
Showing posts with label cometary origin. Show all posts

Friday, February 12, 2021

2019 WU5 - cometary origin?

 This asteroid belongs to the list of Asteroids with comet-like orbit.

From JPL Small-Body Database:

(2019 WU5)
Classification: Outer Main-belt Asteroid          SPK-ID: 3893764
[ 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 7 (heliocentric ecliptic J2000)
 ElementValueUncertainty (1-sigma)  Units 
e.19306979203166171.6908e-07 
a4.3335858368686231.4656e-07au
q3.4969013205930437.463e-07au
i72.040684643866912.1904e-05deg
node221.66456056746071.0021e-05deg
peri180.41933136451690.00041009deg
M357.41548809740560.00028294deg
tp2459024.156231824573
(2020-Jun-23.65623182)		0.0025898TDB
period3295.107075458794
9.02		0.00016716
4.577e-07		d
yr
n.10925289884544215.5424e-09deg/d
Q5.1702703531442021.7486e-07au
 Orbit Determination Parameters
   # obs. used (total)     61  
   data-arc span     3329 days (9.11 yr)  
   first obs. used     2011-11-24  
   last obs. used     2021-01-04  
   planetary ephem.     DE431  
   SB-pert. ephem.     SB431-N16  
   condition code     0  
   norm. resid. RMS     .45354  
   source     ORB  
   producer     Otto Matic  
   solution date     2021-Jan-19 01:09:36  

Additional Information
 Earth MOID = 2.50565 au 
 Jupiter MOID = .257366 au 
 T_jup = 1.753 

Clone Generation
I have generated 100 clones with same nominal orbital paramaters and uncertainty as listed in JPL.

Clones  Target
mean sd   mean sd
q 3.49690139144 7.4916e-07   3.49690132059 7.463e-07
e 0.19306977346 1.6869e-07   0.19306979203 1.6908e-07
i 72.04068365797 2.190239e-05   72.04068464387 2.1904e-05
peri 180.41934713818 0.00040883845   180.41933136452 0.00041009
node 221.6645589917 9.9937e-06   221.66456056746 1.0021e-05
tp 2459024.15632594 0.00257792331   2459024.15623182 0.0025898

Simulation
Mercury 6 simulator - Main integration parameters:

)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)= 2459000.5
 stop time (days) = -1d8
 output interval (days) = 100
 timestep (days) = 0.05
 accuracy parameter=1.d-12
...
 ejection distance (AU)= 100


Results
37% of the clones (abbreviated as WU_<xx>) have a cometary orgin (i.e., they arrived into the solar system from a distance greater than 100 AU

   Clone    Year
1  WU_100  -56379
2   WU_13  -76730
3   WU_75  -78626
4   WU_60  -82278
5   WU_49  -89951
6   WU_65  -90759
7   WU_68 -104326
8   WU_23 -104646
9   WU_55 -112570
10  WU_61 -116290
11  WU_34 -121402
12  WU_12 -128031
13  WU_20 -128759
14   WU_6 -139418
15  WU_21 -140254
16   WU_5 -145159
17  WU_43 -148811
18  WU_26 -154109
19  WU_62 -154655
20  WU_50 -160938
21  WU_84 -172015
22  WU_88 -174160
23  WU_92 -181595
24  WU_14 -186024
25  WU_33 -188258
26  WU_72 -191679
27  WU_39 -198447
28  WU_99 -219044
29  WU_79 -219399
30   WU_2 -221567
31   WU_8 -225358
32  WU_31 -226367
33  WU_38 -227092
34  WU_52 -229987
35  WU_28 -231880
36  WU_76 -248039
37  WU_18 -261908

The same data are displayed below in a graphical form



In the simulation, there were also many clones that are not physically possible because they seem to have been generated by the sun (i.e., hit the sun in the backward simulation):

the sun was hit by WU_37    at     -52591  
the sun was hit by WU_64    at     -57478  
the sun was hit by WU_29    at     -70918  
the sun was hit by WU_9     at     -71001 
the sun was hit by WU_40    at     -80609  
the sun was hit by WU_22    at     -84348  
the sun was hit by WU_95    at    -101285  
the sun was hit by WU_11    at    -110098  
the sun was hit by WU_57    at    -128350  
the sun was hit by WU_66    at    -152709  
the sun was hit by WU_27    at    -189078  
the sun was hit by WU_80    at    -190586  
the sun was hit by WU_53    at    -200575  
the sun was hit by WU_41    at    -219225 
the sun was hit by WU_63    at    -226575  
the sun was hit by WU_85    at    -239827

Looking in more detail at the clones that have a clear cometary origin, we find some that entered the solar system on a hyperbolic trajectory with V-infinity (km/s) as shown below:

    Clone  V-infinity
 1: WU_100 16.108207
 2:  WU_21 13.756060
 3:  WU_31 11.663052
 4:  WU_55 11.590669
 5:  WU_72  9.704585
 6:  WU_60  8.068643
 7:  WU_92  7.018560
 8:  WU_68  6.375238
 9:  WU_65  5.577997
10:  WU_50  5.496867
11:  WU_84  4.518317
12:  WU_99  3.747645
13:  WU_79  1.179131

Orbital Parameters - Time plots
The simulation time is divided into slots.
In every slot and for every clone, you calculate the min perihelium distance, then you look at the distribution of the values plotting a segment showing the interquantile range.
(similar approach for the other orbital parameters).













Kind Regards
Alessandro Odasso



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Tuesday, January 19, 2021

Trojan 2015 EL77 - cometay origin?

I refer to this MPML message (and related thread) where we discussed about possible cometary objects captured in trojan like orbits.

Sam Deen has found precovery data for 2015 EL77 - the condition code is now 4.6

I used Find_Orb online by Bill Gray to get the updated nominal orbit

"Pseudo-MPEC" for 2015 EL77

Created 2021 Jan 17 20:37:56 UT using Find_Orb

 Astrometry: 
     K15E77L ZC2014 12 10.60290 11 55 11.83 +02 57 42.3          21.5 i      F51
     K15E77L ZC2014 12 10.63036 11 55 12.83 +02 57 34.7                      F51
     K15E77L* C2015 03 10.31054 11 55 34.03 +02 03 16.7          21.3 Vo~4A7m691
     K15E77L  C2015 03 10.32942 11 55 33.38 +02 03 18.8          21.0 Vo~4A7m691
     K15E77L  C2015 03 10.34830 11 55 32.70 +02 03 22.1          20.6 Vo~4A7m691
     K15E77L  C2015 03 17.28001 11 51 28.30 +02 21 36.9          20.7 Vq~4A7mG96
     K15E77L  C2015 03 17.28458 11 51 28.18 +02 21 37.3          20.3 Vq~4A7mG96
     K15E77L  C2015 03 17.28915 11 51 28.10 +02 21 37.9         x20.5 Vq~4A7mG96
     K15E77L  C2015 03 17.29372 11 51 27.86 +02 21 39.0          21.1 Vq~4A7mG96
     K15E77L  C2015 04 10.22495 11 37 57.58 +03 17 25.2          21.8 Vq~4A7mG96
     K15E77L  C2015 04 10.23007 11 37 57.43 +03 17 26.2          21.3 Vq~4A7mG96
     K15E77L  C2015 04 10.23518 11 37 57.27 +03 17 25.8          21.1 Vq~4A7mG96
     K15E77L  C2015 04 10.24029 11 37 57.11 +03 17 26.3          22.1 Vq~4A7mG96
     K15E77L  C2015 04 11.14392 11 37 31.30 +03 18 58.7          21.2 Vo~4A7m691
     K15E77L  C2015 04 11.17458 11 37 30.46 +03 19 02.1          21.3 Vo~4A7m691
     K15E77L  C2015 04 11.20520 11 37 29.57 +03 19 05.2          21.2 Vo~4A7m691
     K15E77L  C2015 04 15.15549 11 35 43.17 +03 25 04.8          20.9 Vo~4A7m691
     K15E77L  C2015 04 15.18213 11 35 42.47 +03 25 07.1          21.0 Vo~4A7m691
     K15E77L  C2015 04 15.20944 11 35 41.76 +03 25 09.4          21.0 Vo~4A7n691
     K15E77L  C2015 04 17.13591 11 34 54.12 +03 27 37.7          21.2 Vo~4A7n691
     K15E77L  C2015 04 17.16280 11 34 53.44 +03 27 39.9          21.3 Vo~4A7n691
     K15E77L  C2015 04 17.18969 11 34 52.71 +03 27 42.1          20.7 Vo~4A7n691
     K15E77L  C2015 04 20.14344 11 33 45.40 +03 30 51.9          20.7 Vo~4A7n691
     K15E77L  C2015 04 20.16935 11 33 44.92 +03 30 54.0          20.9 Vo~4A7n691
     K15E77L  C2015 04 20.19526 11 33 44.26 +03 30 55.6          20.9 Vo~4A7n691
     K15E77L  C2018 09 05.18753522 57 52.75 -09 53 18.0          22.5 g      W84
     K15E77L  C2018 09 05.30735022 57 48.93 -09 53 36.3          22.0 r      W84
     K15E77L  C2018 10 05.99057922 43 38.70 -10 55 51.7          22.1 z      W84
     K15E77L  C2018 10 05.99231522 43 38.67 -10 55 52.0          22.1 z      W84

Station data:
(691) Steward Observatory, Kitt Peak - Spacewatch  (N31.962189 W111.600340)
   US/Arizona.  Observer J. V. Scotti. 0.9-m f/3 reflector + CCD.
(F51) Pan-STARRS 1, Haleakala  (N20.707235 W156.255910)  US/Hawaii.
   Observers N. Primak, A. Schultz, S. Watters, J. Thiel, T. Goggia. Measurer
   PS1 Science Consortium. 1.8-m Ritchey-Chrétien + CCD.
(G96) Mt. Lemmon Survey  (N32.442754 W110.788720)  US/Arizona.  Observers B.
   M. Africano, E. J. Christensen, G. A. Farneth, D. C. Fuls, A. R. Gibbs, A.
   D. Grauer, H. Gröller, R. E. Hill, J. A. Johnson, R. A. Kowalski, S. M.
   Larson, G. J. Leonard, R. G. Matheny, R. H. McNaught, R. L. Seaman, F. C.
   Shelly. 1.5-m reflector + 4K CCD + 10K CCD.
(W84) Cerro Tololo-DECam  (S30.169661 W70.806525)  Chile. 4.0-m f/2.87 reflector +
   CCD.

Orbital elements:  2015 EL77
   Perihelion 2016 Jan 25.44272 +/- 0.0186 TT = 10:37:31 (JD 2457412.94272)
Epoch 2018 Oct  5.0 TT = JDT 2458396.5   Ju: 0.2017           Auto-Find
M  84.64479728 +/- 0.006            (J2000 ecliptic)
n   0.08605985 +/- 5.14e-6          Peri.  219.89562 +/- 0.0027
a   5.08084143 +/- 0.000202         Node     6.39360 +/- 0.00039
e   0.2969684 +/- 2.9e-5            Incl.    5.89755 +/- 0.00018
P  11.45                   H 15.4   G  0.15   U  4.6
q 3.57199199 +/- 2.1e-5    Q 6.58969086 +/- 0.000409
28 of 29 observations 2014 Dec. 10-2018 Oct. 5; mean residual 0".34

Residuals in arcseconds: 
141210 F51  .02+  .44+    150410 G96  .28+  .67+    150417 691  .19+  .12+    
141210 F51  .20+  .21-    150410 G96  .17+  .26-    150417 691  .67-  .38+    
150310 691  .31-  .24+    150410 G96  .07+  .29-    150420 691  1.1-  .67-    
150310 691  .02-  .58-    150411 691  .63-  .14-    150420 691  .46+  .05-    
150310 691  .18-  .21-    150411 691  .22+  .18+    150420 691  .66-  .07+    
150317 G96  .32-  .25+    150411 691  .34+  .21+    180905 W84  .13-  .20-    
150317 G96  .42+  .08-    150415 691  .04+  .09-    180905 W84  .19-  .04+    
150317 G96( 1.7+  .20-)   150415 691  .14+  .02+    181005 W84  .04+  .29+    
150317 G96  .68+  .17+    150415 691  .36+  .08+    181005 W84  .16+  .12+    
150410 G96  .22+  .20+    150417 691  .32+  .12-    

...
 
2015 EL77 - Clone generation 
I generated 100 clones trying to achieve the same orbital parameters and uncertainties as calculated by Find Orb:

 Clones  Target

mean sd   mean sd
q 3.57199229514 2.087558e-05   3.57199199 2.1e-05
e 0.29696990335 2.88812e-05   0.2969684 2.9e-05
i 5.8975243641 0.00018175059   5.89755 0.00018
peri 219.89550304999 0.00266661496   219.89562 0.0027
node 6.39364451828 0.00039272039   6.3936 0.00039
tp 2457412.94469156 0.01838184197   2457412.94272 0.0186

 

Backward simulation

Mercury6 integrator package version 6 by J. E. Chambers

Main parameters:

)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)= 2459167.50000
 stop time (days) = -1d8
 output interval (days) = 100
 timestep (days) = 0.05
 accuracy parameter=1.d-12
 ejection distance (AU)= 100

A clone is considered to be a comet if it enters the solar system from a distance greater than arbitrary threshold = 100 AU

Simulation results

65 out of 100 clones have a cometary origin (i.e.arrived into solar system in the simulation window - back up tp 10^8 days in the past)

Clones are abbreviated as EL_<xx> with 01 <= xx <= 100

   Beginning the main integration.

 EL_64    ejected at     -46141  7  7.66483
 EL_22    ejected at     -54004  7 13.04497
 EL_95    ejected at     -58787  2 10.36615
 EL_97    ejected at     -61738  3 29.42279
 EL_3     ejected at     -62842 10 12.43896
 EL_89    ejected at     -62843  6 10.48001
 EL_25    ejected at     -66320  1 28.69544
 EL_11    ejected at     -67224  4 18.80180
 EL_66    ejected at     -69523  6  6.72318
 EL_91    ejected at     -76290  5 28.23664
 EL_12    ejected at     -77604 12 16.11145
 EL_33    ejected at     -79343 12 15.19062
 EL_6     ejected at     -80788 10 16.99425
 EL_48    ejected at     -83533  4 17.92191
 EL_71    ejected at     -87015  1 25.24236
 EL_87    ejected at     -88939  8 17.07250
 EL_41    ejected at     -91238  5 19.99891
 EL_1     ejected at     -93576  5 26.00883
 EL_52    ejected at     -97525  3 28.56210
 EL_76    ejected at     -98392  6 27.63136
 EL_82    ejected at    -100242  9 30.44242
 EL_34    ejected at    -109661  5  2.91190
 EL_63    ejected at    -111694  8  8.28741
 EL_39    ejected at    -112995  7 23.17464
 EL_21    ejected at    -113013 10 14.02220
 EL_59    ejected at    -113502  9 19.60363
 EL_86    ejected at    -114409  9  6.10029
 EL_68    ejected at    -115449  9  2.07513
 EL_55    ejected at    -122395  2 18.18319
 EL_62    ejected at    -123044  6 23.36232
 EL_96    ejected at    -123200 11 19.24066
 EL_29    ejected at    -132608  9 22.62730
 EL_45    ejected at    -132867  3 25.99649
 EL_7     ejected at    -132914  8  5.74390
 EL_38    ejected at    -138752  1 11.96940
 EL_85    ejected at    -139152  9  7.87151
 EL_14    ejected at    -143728 11 26.00313
 EL_75    ejected at    -144479  8 15.54337
 EL_44    ejected at    -148125 11 10.01233
 EL_74    ejected at    -148379  2 11.01097
 EL_70    ejected at    -150626 11 15.21742
 EL_46    ejected at    -150909 11 14.27464
 EL_92    ejected at    -158751  2  6.56521
 EL_4     ejected at    -171194  3  3.69811
 EL_88    ejected at    -191422 11 24.83374
 EL_18    ejected at    -191433 10 30.34998
 EL_32    ejected at    -194882  9  1.96188
 EL_16    ejected at    -199430  6 16.42980
 EL_31    ejected at    -203156  2 25.26967
 EL_77    ejected at    -205024  9 24.15732
 EL_43    ejected at    -211742  2 14.19068
 EL_61    ejected at    -212216  3 12.36277
 EL_50    ejected at    -219919  2 29.90785
 EL_93    ejected at    -224512  9  8.91093
 EL_49    ejected at    -224744  7  2.99308
 EL_23    ejected at    -225546  1 28.97203
 EL_28    ejected at    -231532  2 28.98184
 EL_78    ejected at    -231695 11 22.50623
 EL_15    ejected at    -233462  2  6.20325
 EL_36    ejected at    -239025  4  8.76140
 EL_67    ejected at    -241109  9  5.85502
 EL_60    ejected at    -246440  5 24.49606
 EL_65    ejected at    -260950  5 10.65600
 EL_10    ejected at    -266269  3  8.22146
 EL_99    ejected at    -273480  3 21.02202

The arrival time distribution into the solar system is shown graphically below:

Curiosity: 7 clones arrived on a hyperbolic trajectory with the following V-infinity (Km/s):

         ast         V
1: EL_76.aei 5.2104487
2: EL_93.aei 4.9340891
3: EL_21.aei 3.0706005
4:  EL_4.aei 2.8995143
5: EL_68.aei 2.8558247
6: EL_52.aei 2.2027882
7: EL_36.aei 0.6715961

If we take all 100 clones togetherand divide the simulation time into slots, we can see the distribution of the orbital parameters.

Orbital Param distribution

In every time slot, we calculate the minimum perihelium for every clone and then we show the distribution of these distances for all clones (from 25th to 75th quartile).

Perihelium q

Eccentricity e

Inclination i

Argument of Perihelium

Ascending Node

Peri + Node

Cheers,

Alessandro Odasso











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