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Kepler system with two planets sharing an orbit! (Read 2676 times)
EDG
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Kepler system with two planets sharing an orbit!
02/27/11 at 15:38:40
 
http://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit. html
 
Apparently there's a planet in a stable orbit at one of the L4/L5 points in this system! (star KOI-730 is KID 10227020)
 
full paper at: http://arxiv.org/abs/1102.0543
 
Might be worth a closer look in gravsim?
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frankuitaalst
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Re: Kepler system with two planets sharing an orbi
Reply #1 - 02/28/11 at 10:56:10
 
Interesting , but it seems also possible that the two planets are in another resonance . This is due to the low detectability - not constant visability- of the system .  
I've been searching to find the expected masses and proper orbital elements but cannot find it - yet -
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Re: Kepler system with two planets sharing an orbi
Reply #2 - 03/02/11 at 14:11:27
 
Here's my attempt of the simulation of the above described system : KOI730 , consisting of 4 planets , which are believed to be on a 6:4:4:3 resonance.  
 
The animation shows the orbits in rotating frame on the third planet (in white) which is believed to be somewhat larger than its coorbital ( in yellow) .  
The animation was run for ca. 45 years .  
Each frame covers 4 orbits of the outermost planet .
 
The simulation was created as following :  
Assumptions : central body has sun mass
Orbits are circular (e=0) with no individual inclinations .  
 
The paper gives the planets radii , from which the mass of the individual planets are calculated using the formula in the paper .  
The individual Sma can be deduced from the observed periods ( which are between 8-12 days) .
Above data are enough to calculate the initial conditions .  
 
The system shows a lot of dynamics . Anxious to see how it evoves on larger timescales...
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KOI730_Animation_RotFrame.gif
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EDG
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Re: Kepler system with two planets sharing an orbi
Reply #3 - 03/03/11 at 02:04:34
 
I've got periods of: 14.785, 9.84978, 9.85997, and 7.38469 days for the planets (from outermost to innermost), and orbital radii of 0.12, 0.092, 0.092, and 0.076 AU respectively.
 
As for the star, I've got a radius of 1.1 Sols and a mass of 1.07 Sols.  
 
(from the excel planet and star list on my blog, which was transcribed from the Kepler discovery paper).  
 
I dunno if the new paper updates that at all though?
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Re: Kepler system with two planets sharing an orbi
Reply #4 - 03/03/11 at 12:11:15
 
Quote from EDG on 03/03/11 at 02:04:34:
I've got periods of: 14.785, 9.84978, 9.85997, and 7.38469 days for the planets (from outermost to innermost), and orbital radii of 0.12, 0.092, 0.092, and 0.076 AU respectively.

As for the star, I've got a radius of 1.1 Sols and a mass of 1.07 Sols.

(from the excel planet and star list on my blog, which was transcribed from the Kepler discovery paper).

I dunno if the new paper updates that at all though?

Thanks for drawing my attention to this paper . I've inputted the new parameters in the sim and got more or less the same result .  
One unknown however are the mean anomalies . Tried out some configurations and saw that if I put the second coplanar at 180 then the system gets really excited .  
Of course the system is very "packed" , 4 planets each having about a mass of 10 Earths orbiting so closely...
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