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Showing posts with label Mercury simulator. Show all posts
Showing posts with label Mercury simulator. Show all posts

Friday, August 18, 2017

Asteroid (2017 OC9) - an extinct QHC?

I wonder whether Hilda asteroid (2017 OC9) was once a comet.

Almost two months ago, there was a nice example of a Hilda asteroid that showed a cometary activity:

Cometary behaviour of Hilda asteroid  (457175)  2008 GO98
As described here by GAMP's (Gruppo Astrofili Montagna Pistoiese, i.e. Pistoia Mountains Astronomical Observatory - MPC code 104) member Paolo Bacci, on the night of July 3rd, 2017, Mt. Lemmon Survey (G96) found that a Hilda asteroid (457175)  2008 GO98, at the time with a brightness of ~16.5 mag, showed a widespread 7/8" coma and a tail with a length of ~15" with PA 260°. 

Observations were subsequently confirmed by the observatory of the Steward Observatory, Mt. Lemmon Station (I52).

The Minor Planet Center on the same day published MPEC 2017-N50, announcing the asteroid cometary activity.

From the Pistoia Mountain Astronomical Observatory (code MPC 104), GAMP members Paolo Bacci and Martina Maestripieri  captured 50  images of the asteroids and they found that the asteroid showed a diffused ~ 16'' arc coma and a long tail ~ 15.3" .

This fact is not completely unexpected.

As described in the paper "Comet candidates among quasi-Hilda objects", there is a dynamical criteria to identify potential candidates in the unstable quasi-Hilda region, the so called Toth rule based on the calculation of horizontal and vertical components (k,h) of eccentricity in Lagrangian elements.

In that paper Asteroid (457175)  2008 GO98 was identified as a potential candidate.

More about the nature of this object can be found in this article  (thanks to David Rich for showing me his blog).


Hilda asteroid (2017 OC9)


It seems to me that this Hilda object satisfies the Toth rule so it might be a candidate to be an extinct comet .

I made a simulation using the Mercury6 simulator ("A Hybrid Symplectic Integrator that Permits Close Encounters between Massive Bodies''. Monthly Notices of the Royal Astronomical Society, vol 304, pp793-799.).

The object uncertainty is still extremely high (orbit condition code 9), so the simulation based only on the nominal parameters is far from being conclusive; anyway, just to have an idea of the possible behaviour, it seems that the object could have arrived from the outskirts of the solar system (100 AU) about 1,2 Millions years ago.

I would be interested to know from expert astromomers if this is a real possibility and if they think that this case deserves a deeper analysis when the orbit will be better known.

Kind Regards,
Alessandro Odasso


Wednesday, December 9, 2015

(111298) = 2001 XZ55 versus 2008 YL20

See an update about this case received on Dec 10th: look at this MPML msg.



===============================================
I am looking again at these two asteroids.

A couple of years ago, as clearly explained by Bill Gray (see MPML msg ), it was a bit too early to make meaningful simulations trying to go back in the past as far as about 25000 years ago.

Now the orbit uncertaintly of asteroid 2008 YL20 has improved from +/- 1.62e-6 degrees /day to +/-1.1568e-08 degrees/day.

I tried a new simulation to investigate the possibility that these two asteroids separated in the past and I got a new result consisting in a nominal distance of about 4000 km, relative velocity about 15 cm/s. This event occurred about 34000 years ago.

The uncertainty is 1.1568e-08 * 365 * 34000 = 0.14 degrees that at an average distance of 2.39 AU corresponds to an uncertainty of about 0.0057 AU (i.e. three time the moon-earth distance).

So ... on one side no proof that these asteroids separated but it seems to me that this pair is still interesting.

More details looking the JPL Small Body Data:

(111298) = 2001 XZ55
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 11 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .1837905901861221 6.7074e-08
a 2.391320808768463 2.2177e-08 AU
q 1.951818546000553 1.6999e-07 AU
i 3.192061836722895 7.0356e-06 deg
node 111.491991193275 0.00011791 deg
peri 297.8338388091076 0.0001197 deg
M 257.5887075379197 2.2491e-05 deg
tp 2457584.738198736595
(2016-Jul-15.23819874)
8.7199e-05 JED
period 1350.688466278188
3.70
1.879e-05
5.144e-08
d
yr
n .2665307426456207 3.7078e-09 deg/d
Q 2.830823071536374 2.6253e-08 AU


2008 YL20
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 8 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .1837937583380851 5.5869e-07
a 2.391150352530784 6.9177e-08 AU
q 1.951671842487714 1.3831e-06 AU
i 3.193600462494826 1.3927e-05 deg
node 111.4717983197325 0.00025271 deg
peri 298.0606134273407 0.00030036 deg
M 320.5524746963916 0.00012064 deg
tp 2457348.487835047940
(2015-Nov-21.98783505)
0.00045708 JED
period 1350.544050792078
3.70
5.8608e-05
1.605e-07
d
yr
n .2665592431352864 1.1568e-08 deg/d
Q 2.830628862573854 8.1891e-08 AU


Mercury Simulator Results

Simulation parameters:

 algorithm (MVS, BS, BS2, RADAU, HYBRID etc) = bs2
 start time (days)= 2457387.5
 stop time (days) = -17.3d6
 output interval (days) = 20
 timestep (days) = 0.1
 accuracy parameter=1.d-12

The result shown as a graph (done with R package):




Kind Regards,
Alessandro Odasso



      Mercury Simulator - Mercury6
      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.

Tuesday, November 24, 2015

11842 Kap'bos (1987 BR1) vs 436415 (2011 AW46)

11842 Kap'bos (1987 BR1) is an interesting asteroid indeed!

First of all, looking at proper elements (see this page), this asteroid has already been recognized to be associated to (228747) 2002 VH3

Furthermore, but this is not sure, it may be even more strictly associated to 436415 (2011 AW46)

JPL Small-Body Database Browser

11842 Kap'bos (1987 BR1)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 14 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .09426143976452217 5.4457e-08  
a 2.250221196226988 1.1502e-08 AU
q 2.038112106481987 1.1993e-07 AU
i 3.688461615022471 5.8652e-06 deg
node 272.8444791596755 7.5115e-05 deg
peri 172.3596586176659 8.1653e-05 deg
M 181.7294574254017 3.145e-05 deg
tp 2457811.038885071140
(2017-Feb-26.53888507)
0.00010929 JED
period 1232.923821576616
3.38
9.4533e-06
2.588e-08
d
yr
n .2919888428626886 2.2388e-09 deg/d
Q 2.462330285971989 1.2586e-08 AU


436415 (2011 AW46) 
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 8 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .09435201650783409 1.8231e-07  
a 2.25006679453928 5.9552e-08 AU
q 2.03776845519718 4.095e-07 AU
i 3.688904837606787 1.5844e-05 deg
node 272.8087674388969 0.00022201 deg
peri 172.3636156199904 0.0002396 deg
M 151.7058568204286 9.5288e-05 deg
tp 2456680.993016870443
(2014-Jan-23.49301687)
0.00031517 JED
period 1232.7969258828
3.38
4.8942e-05
1.34e-07
d
yr
n .2920188981994789 1.1593e-08 deg/d
Q 2.462365133881379 6.5171e-08 AU


This is the result of a simulation made with Mercury6 software (graphs made with package R):



Looking at nominal parameters, it seems that these two asteroids had a very close encounter (nearly 9000 km) with a relative velocity of about 30 cm/s about 11500 years ago.

I do not know whether this is true and, if yes, whether this is just a coincidence or these two asteroids separated in that moment from a common body.

Kind Regards,
Alessandro Odasso

Tuesday, November 17, 2015

421781 (2014 QG22) vs 53576 (2000 CS47)

These two asteroids are a potentially interesting couple.
I do not know if this couple is already known and if it is really a couple with a common origin.

Let's look at the JPL data, showing very similar orbital parameters:
421781 (2014 QG22)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 5 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .1415490034245739 7.6497e-08
a 2.219666740174171 5.0262e-08 AU
q 1.905475125167845 1.6225e-07 AU
i 5.547751979163497 1.1933e-05 deg
node 270.894647775993 0.00023172 deg
peri 334.1685226014454 0.00025596 deg
M 170.5342535281013 0.00011344 deg
tp 2456628.311384753553
(2013-Dec-01.81138475)
0.00037629 JED
period 1207.897517520007
3.31
4.1027e-05
1.123e-07
d
yr
n .2980385295758646 1.0123e-08 deg/d
Q 2.533858355180498 5.7376e-08 AU
 Orbit Determination Parameters
   # obs. used (total)      49  
   data-arc span      3697 days (10.12 yr)  
   first obs. used      2004-08-14  
   last obs. used      2014-09-28  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .55494  
   data source      ORB  
   producer      Otto Matic  
   solution date      2015-Jan-08 13:35:22  

Additional Information
 Earth MOID = .893565 AU 
 T_jup = 3.631 

53576 (2000 CS47)
Orbital Elements at Epoch 2457200.5 (2015-Jun-27.0) TDB
Reference: JPL 11 (heliocentric ecliptic J2000)

 Element Value Uncertainty (1-sigma)   Units 
e .1413172303277337 5.195e-08
a 2.219866104654218 1.5604e-08 AU
q 1.906160775046069 1.1284e-07 AU
i 5.548153406788004 6.1614e-06 deg
node 270.899183954788 6.9605e-05 deg
peri 334.2072656882382 7.5251e-05 deg
M 151.5995810376835 2.9164e-05 deg
tp 2456691.773809093385
(2014-Feb-03.27380909)
9.8063e-05 JED
period 1208.060256319952
3.31
1.2737e-05
3.487e-08
d
yr
n .2979983805581422 3.142e-09 deg/d
Q 2.533571434262367 1.7809e-08 AU

Orbit Determination Parameters
   # obs. used (total)      610  
   data-arc span      7436 days (20.36 yr)  
   first obs. used      1994-07-08  
   last obs. used      2014-11-16  
   planetary ephem.      DE431  
   SB-pert. ephem.      SB431-BIG16  
   condition code      0  
   fit RMS      .49974  
   data source      ORB  
   producer      Otto Matic  
   solution date      2015-Mar-09 16:42:10  

Additional Information
 Earth MOID = .894238 AU 
 T_jup = 3.631 

 I tried to run the Mercury simulator (BS2 integrator, timestep 1 day) with the nominal parameters, with this result (graph done with the R package)



Kind Regards,
Alessandro Odasso

Friday, August 7, 2015

(356713) 2010 GS25 vs 2014 QX220

These two asteroids have similar orbits:
(356713) 2010 GS25
2014 QX220


Mean motion uncertainty a little less than 10^-8 deg/day

I wonder if these two asteroids originated from a common parent body about 10Kyears ago.

Using the Mercury simulator by John Chambers on the nominal parameters, we have this result:


Year -8168
Distance = 0.0000232 (AU) about 3500 km
Relative Velocity = 7.270e-08 (AU/Day) about 12 cm/s


Kind Regards,
Alessandro Odasso