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Cloud Invader (Read 3456 times)
frankuitaalst
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Cloud Invader
06/01/08 at 05:24:56
 
I was wondering how a cloud of particles in "rest" would react to an invasion of a big planet moving towards it .  
I suspect the planet would change the cloud gradually in a pear-form and leave a pattern of emptyness in the trail behind , eventually some planets could be "captured " .  
500 Earth planets were created around a central Earth , giving them more or less a "rest" velocity .  
A larger body (100 MJup) was added , initially at 200 AU , moving towards the cloud at 20km/s.  
Heres the result of a simulation ...covering about 30 years .  
Contrary to intuition the larger body seems to go straight trough to cloud ...
I guess the initial speed of 20 km/s was set to high , as a result the system gets not enough time to feel the attraction force of the invader .  
If one wants I can post also  the initial and end .gsim file .  
Edit : after running the second sim hereunder I realised that the heavy body might have had 10MJup instead of 100MJup ; typeinput error  embarrassed
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« Last Edit: 06/01/08 at 11:16:23 by frankuitaalst »  

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frankuitaalst
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Re: Cloud Invader
Reply #1 - 06/01/08 at 09:34:23
 
Increasing the Invaders Mass and giving it a smaller velocity results in this rather amazing result ..
Same 500 Earths as above , but this time a 100 Jup body approaches at 1km/s from 100 Au distance .  
All bodies are attracted , swing by 100Jup and seem to end up in an elliptical (or hyperbolic ? )orbit around Jupiter ...
Here are the gaps visible in front and behind 100Jup  
Screensize was reduced to match the gifSize.
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Cloud100JupMassSmallSize.gif
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Tony
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Re: Cloud Invader
Reply #2 - 06/01/08 at 10:35:35
 
This is somewhat similar to the "Sedna" simulation:
http://www.orbitsimulator.com/gravity/articles/sedna.html
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frankuitaalst
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Re: Cloud Invader
Reply #3 - 06/01/08 at 11:13:52
 
Yes , indeed there is . I'm not sure if the bodies in my simulation are captured or not . May be able to calculate it from the initial conditions I think .
I guess Alessandro Morbidelli had to do some trials before getting to his result . Nice that GravSim matches up with the Swift_rmvs3 orbit integrator . Any idea what this might be ?  
 
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Re: Cloud Invader
Reply #4 - 06/01/08 at 12:02:08
 
Quote from frankuitaalst on 06/01/08 at 11:13:52:
Yes , indeed there is . I'm not sure if the bodies in my simulation are captured or not . May be able to calculate it from the initial conditions I think .
I guess Alessandro Morbidelli had to do some trials before getting to his result . Nice that GravSim matches up with the Swift_rmvs3 orbit integrator . Any idea what this might be ?


I'm not sure what your question is.
 
Here's a pdf of Morbidelli's paper:  http://www.boulder.swri.edu/~hal/PDF/CR105.pdf
There are many hypothesis about Sedna's origin.  Section 6 describes the scenerio I simulated.  Figure 9 looks exactly like what you get when you perform this with Gravity Simulator.
 
There's lots of things mentioned in that paper that you can try with Gravity Simulator.
 
If you want to know if your bodies are captured, just run the simulation longer and see if they complete orbits around the planet.
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frankuitaalst
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Re: Cloud Invader
Reply #5 - 06/01/08 at 14:25:32
 
Thanks for the link to the paper ... I'll take a look into it .  
My question was if the mentionned integrator is some standard in astronomy .
Googling for it "Swift_rmvs3 orbit integrator"  I arrived at a paper by A. Moullet, E. Lellouch et others describing the orbit of 1999TZ1, a suspected Jovian Trojan . They integrated for 1Gy!! in order to prove the asteroid indeed is a trojan and is stable . It seems to be stable .  
BTW : I don't know how this guys are able to integrate for 1Gy in a reasonable amount if time .  
The asteroid is 51+/- 5 km wide and seems to be in the L5 point .  
It's orbit however is quite dynamic . I'll post an animation in the "asteroids" .  
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Re: Cloud Invader
Reply #6 - 06/02/08 at 04:19:04
 
Quote from frankuitaalst on 06/01/08 at 14:25:32:
Thanks for the link to the paper ... I'll take a look into it .
My question was if the mentionned integrator is some standard in astronomy .
Googling for it "Swift_rmvs3 orbit integrator"  I arrived at a paper by A. Moullet, E. Lellouch et others describing the orbit of 1999TZ1, a suspected Jovian Trojan . They integrated for 1Gy!! in order to prove the asteroid indeed is a trojan and is stable . It seems to be stable .
BTW : I don't know how this guys are able to integrate for 1Gy in a reasonable amount if time .
The asteroid is 51+/- 5 km wide and seems to be in the L5 point .
It's orbit however is quite dynamic . I'll post an animation in the "asteroids" .

 
Hi Frank,
 
Download the Swift Integrator here:
 
- http://www.boulder.swri.edu/~hal/swift.html
 
Inside de package there is Swift_rmvs3.
 
I donīt play with Swift but Morbidelli say about it:
 
Quote:
I'm certainly willing to certify the importance that the swift package has had and still has in the planetary dynamics community. The package includes two main integrators: swift_mvs1 and swift_rmvs3, which are now largely in use by dynamicists and have become a standard in the field.

Swift_mvs integrates in a symplectic way the dynamics of planets and massless particles, provided that close encounters do not occur. The algorithm is due to Wisdom and Holman who, however, never distributed their code. I'm sure that the public availability of swift_mvs has boosted the use of symplectic integrations in celestial mechanics, which otherwise would have taken several years.

Swift_rmvs3 is an extension of swift_mvs that can deal with close encounters between massless particles and planets. Due to its high speed, this code allowed integrations of the evolution of thousands of bodies, from their source regions (resonances in the asteroid or in the Kuiper belt) to their ultimate dynamical fate (collision with the Sun or with a planet, or ejection on hyperbolic orbit). This has allowed studies of the origin, the dynamics and the steady state orbital distributions of meteoroids, Near Earth Asteroids and short periodic comets in a quantitative statistical sense.

A discussion of the revolutionary role that the swift package has had in celestial mechanics, and a review of the major results achieved with its use can be found in my paper for "Annual Reviews of Earth and Planetary Sciences", which will appear in 2002 but is downloadable from the page http://www.obs-nice.fr/morby/Invited_list.html.

Alessandro Morbidelli
Permanent Research Astronomer
Observatoire de la Cote d'Azur

 
- http://www.boulder.swri.edu/swifter/testimony.html
 
A version that include the Yarkovsky diurnal and seasonal forces over a body here:
 
- http://sirrah.troja.mff.cuni.cz/~mira/mp/tmp/images/swift_rmvsy.tar.gz
 
More about this version here:
- http://sirrah.troja.mff.cuni.cz/~mira/mp/
 
 
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The diversity of the phenomena of nature is so great,and the treasures hidden in the heavens so rich,precisely in order that the human mind shall never be lacking in fresh nourishment.
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frankuitaalst
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Re: Cloud Invader
Reply #7 - 06/03/08 at 12:08:13
 
Thanks very much Apodman for the links ...! I'll be out for a while reading all about this !  Wink
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