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 Kozai (kinda) - sim 4 (Read 4846 times)
 EDG Ultimate Member oh, crumbs!!! Posts: 611 Gender: Kozai (kinda) - sim 4 11/09/06 at 23:38:03   Just for the hell of it, I decided to do the Sim 3 run, but with neither the planet nor the companion in an inclined orbit. So they're in the same plane, but the companion is in an orbit with eccentricity of 0.8.     So far it looks a bit curious. The planet's eccentricity peaked around 0.1 around 210,000 years and is going back down - I dunno if it'll come back up again later on, I'll continue to run the program to see what happens. The planet's Arg of Peri is merrily rotating slowly through 360° over time, inclination is still at zero. Back to top (formerly known as Mal)   IP Logged
 Tony YaBB Administrator Posts: 1058 Gender: Re: Kozai (kinda) - sim 4 Reply #1 - 11/10/06 at 01:03:59   I don't think the rise to 0.1 ecc and its subsequent decline will be periodic, but rather chaotic.  But I'm anxious to hear the results.  It may be similar to what Jupiter does to Earth and especially to Mars.  The planes are too similar for the Kozai mechanism to work its magic.  But Earth's and Mars' eccentricity does vary between a max ecc and nearly circular.   As far as inclination, if both the planet and companion were started with exactly 0 for the inclination, then inclination will never change, guaranteed.  You've simply set up a 2-D simulation.  Inclination can only change when something torques up or down on an object, which is impossible if all objects have a value of 0 for their z-axis position component.  Consider the following formula from the source code: Quote:fz = (dz / D) * f; The acceleration on the z-axis equals the distance on the z axis divided by total distance times total acceleration.  dz, the distance between 2 objects on the z-axis, will always be zero if all your objects have 0 for their z-axis position component. Back to top IP Logged
 EDG Ultimate Member oh, crumbs!!! Posts: 611 Gender: Re: Kozai (kinda) - sim 4 Reply #2 - 11/10/06 at 07:16:17   Oh, I figured the inclinations would remain at zero. I just wanted to see if the eccentricity cycled, and so far it looks like it does - it goes from 0 to 0.1 to 0 in about 450,000 years and appears to be repeating itself... I'll post a graph tonight. Back to top (formerly known as Mal)   IP Logged
 EDG Ultimate Member oh, crumbs!!! Posts: 611 Gender: Re: Kozai (kinda) - sim 4 Reply #3 - 11/10/06 at 20:52:06   872,400 years (planet eccentricity and Arg of Peri):     I changed to a 2048 second timestep around 760,000 years, doesn't seem to have made any noticeable difference to anything. Back to top (formerly known as Mal)   IP Logged