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Binary Eccentricity Test - volunteers needed! (Read 30373 times)
EDG
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Re: Binary Eccentricity Test - volunteers needed!
Reply #75 - 10/29/06 at 15:19:41
 
Frank, can you please repost all your 5 earth sims/results in its own thread? Your posts about this are scattered somewhat, I've lost track on what your starting conditions were. Putting it all in its own thread would make it easier to follow. Smiley
 
I got some questions about this but I'll post them if/when you've got everything in one place, you may have already answered them elsewhere Wink
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frankuitaalst
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Re: Binary Eccentricity Test - volunteers needed!
Reply #76 - 02/03/07 at 07:12:54
 
Remembering the Kozai ?
Quote from Tony on 10/25/06 at 20:57:12:
I ran this at time step 4096.

I created a simulation exactly like yours, except the secondary object was 10 AU instead of 750, 0 eccentricity and 90 inclination.

Using formula 2, I computed the Kozai Period to be 289 years.

I ran it and I got:

http://orbitsimulator.com/gravity/kz99.GIF

So in this quick example, it seems right on the money.

Here's the sim:
http://orbitsimulator.com/gravity/simulations/kz99.gsim

 
I ran this Kozai kz99 again with Picard and got the following amazing  Shocked result  ...
The calculated period of the oscillation also matches as can be seen from the picture herunder , but , whats interesting is that the inclination really jumps from lets say 20° to nearly 180° after about 150 years . What does an inclination of nearly 180° mean by the way ??  
I noticed that the change took place when the planet was at the far point from the sun and turned his back , ie it returned clockwise and continued turning clockwise , where it was revolving anti-clockwise before ...
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kozaikz99.jpg
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Re: Binary Eccentricity Test - volunteers needed!
Reply #77 - 02/03/07 at 07:49:02
 
Wondering how the system would evolve I ran the same sim as above for about 2200 years and got the weird result hereunder .  
It seems the system is not quite stable , changing , or seeking its "home" inclination about every 150 years .  
It also seems that once the initial condition is left the max. eccentricity always gets to about 1 , but  the 0 eccentricity is hardly achieved again
The frequency of the Kozai cycle  however is rather stable .  
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Kozai99-2000y.jpg
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Re: Binary Eccentricity Test - volunteers needed!
Reply #78 - 02/03/07 at 09:56:01
 
Quote:
I ran this Kozai kz99 again with Picard and got the following amazing result ...
The calculated period of the oscillation also matches as can be seen from the picture herunder , but , whats interesting is that the inclination really jumps from lets say 20° to nearly 180° after about 150 years . What does an inclination of nearly 180° mean by the way ??
I noticed that the change took place when the planet was at the far point from the sun and turned his back , ie it returned clockwise and continued turning clockwise , where it was revolving anti-clockwise before ...

 
If memory serves me correctly 180 deg and greater = retrograde motion.  Also, looking at the graphs I'd say that over geologic time of the system the planemo would be ejected.  I would be interested in seeing a longer run with [e, a, i] vs [P,S] of the planemo.
 
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Re: Binary Eccentricity Test - volunteers needed!
Reply #79 - 02/03/07 at 10:34:17
 
ok , I will run it over a longer time ... In the meantime I created a screenshot at about 350 years of simaulation which shows that the planet comes almost as close as the radius of the sun , so a good chance of collision exists ...
This also means that , while the system has a companion at 90° ,the system  is not stable at all and is due to a lot of ...chaos ...
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Kozai99Distance.jpg
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Re: Binary Eccentricity Test - volunteers needed!
Reply #80 - 02/03/07 at 11:20:00
 
you're right ... the planet decided to evolve the other way several times ... and is ejected .... The system survived more than  20 close passes with the sun , but after about 3000 years the fun was over , and the planet is ejected . Hereunder the Excel-Graph of inclination and SMA ( in m, instead of AU ) vs. time .... At the last encounter with the sun the planet came as close as 420*10E-6 Au of the sun ...
I cut the graph at ~3000 years , because the SMA was rising out of proportion...
Am I right when I see that the Kozai frequency gets exited the closer time approaches 3000 years ?  
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Kozai99-3000yrs.jpg
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Re: Binary Eccentricity Test - volunteers needed!
Reply #81 - 02/03/07 at 13:11:57
 
If you'll notice in your graph the kozai period is in a continual decrease with a distinct acceleration after  ~2500a.
 
I'm currently working on a large project.  A recode of the "Stargen" program by Eldacur.  after I have it completed I will also add an option to export the system to Gsim format.  I'm hoping to have a beta ready by the end of march or earlier.
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Re: Binary Eccentricity Test - volunteers needed!
Reply #82 - 02/03/07 at 13:17:51
 
oh one other question, What are the masses of [P, S] and what is the periapsis of the 2.
 
One reason the planemo may have been ejected is it may have move into the binary zone of instability.
I'll post more about this zone at a later time, when time permits.
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Re: Binary Eccentricity Test - volunteers needed!
Reply #83 - 02/03/07 at 14:12:50
 
The data were taken from this sim :
http://orbitsimulator.com/gravity/simulations/kz99.gsim  
The companion is rather "heavy" , almost the suns mass .
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Re: Binary Eccentricity Test - volunteers needed!
Reply #84 - 02/03/07 at 14:13:30
 
Abysoft is right, 180 inclination is a retrograde orbit.  But I don't think that's what's happening in your graph.  I can't see the entire y-axis scale on the right, but it looks like inclination jumped to 1600?  I'm confused there, because Gravity Simulator shouldn't be outputting numbers this high for inclination.
 
Usually, when I see a graph like that it is because some value crosses the 360 mark and jumps to 0, or crosses 0 to 360.  And sometimes, inclination and mean anomoly can give you 'off by 180' errors, but usually for orbits with 0 inclination as lots of orbital properties are measured from longitude of the ascending node, and an orbit with no inclination has no ascending node.
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Re: Binary Eccentricity Test - volunteers needed!
Reply #85 - 02/03/07 at 14:44:41
 
not to worry about GravitySimulator , it works perfect . Smiley  
To avoid decimals I got the output in integers , multiplying the inclination with 1000. This means 180000 on the scale = 180 degrees .  In the sim I saw the planet make retrograde orbits .
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