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Author Topic: Planning for my next long run simulation  (Read 2687 times)

emarksmi

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Planning for my next long run simulation
« on: January 21, 2017, 07:39:31 PM »
With my Rogue Jupiter simulation entering middle age (I'm thinking it probably has 15-20 Thousand simulated years to go and still be interesting), I'm planning my next project.  Now I'm open to suggestions if there is anything that somebody wants to see simulated and run for a long time, but at the moment I'm thinking of the following:

Solar System Collision.  Start with our Solar System, probably the base simulation that loads with the program, but add a second solar system that will pass by/through ours.  Not just a rogue star or planet, but a full system.  I'm thinking of having it come in at about a 10 degree angle to our solar system (with the logic that the stars in the galaxy are mostly traveling in roughly the same direction) but with the ecliptic of the other system tilted at about 30 degrees to ours.  The other star would be roughly sun mass.  The "aim point" would be at about Neptune's orbit (ie, the stars would be set up initially to pass about 30 AU from each other) and I'd start the simulation several thousand years before closest approach.

Now, my question is, is there an easy way to create the other solar system or do I need to do it from scratch?  I want a full, stable system with several planets, an asteroid belt, and a Kuiper Belt.  I don't see pre-made systems that I can add.

Thoughts/Ideas?

SuperPotato

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Re: Planning for my next long run simulation
« Reply #1 on: January 24, 2017, 06:42:22 PM »
Launch the star and add planets to it as it is going.
« Last Edit: January 24, 2017, 06:46:48 PM by SuperPotato »

SuperPotato

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Re: Planning for my next long run simulation
« Reply #2 on: January 24, 2017, 06:51:30 PM »
See, yeah I just tested you can add planets as it is going. I also got a planet with lights so this is going to be interesting.
 ;D

emarksmi

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Re: Planning for my next long run simulation
« Reply #3 on: January 24, 2017, 09:04:23 PM »
I was playing with that a little and I'm not sure it will work.  The problem is that I can only set the aim point out to 2AU and I'm looking to run the closest approach of the stars at about 30 AU.  I think I have a way to do it, but I'm going to have to experiment.

Physics_Hacker

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Re: Planning for my next long run simulation
« Reply #4 on: January 24, 2017, 09:49:14 PM »
I was playing with that a little and I'm not sure it will work.  The problem is that I can only set the aim point out to 2AU and I'm looking to run the closest approach of the stars at about 30 AU.  I think I have a way to do it, but I'm going to have to experiment.

Unfortunately, if you want a really far out nearest approach like that, you're either going to have to set a higher velocity than if you wanted a very close approach, or you'll have to aim much further than the sun than you actually want it to go, because it will dramatically curve toward the sun as it goes past, especially the star being near the mass of our own sun, and if you don't set the velocity high enough (which what logically seems "high enough" usually actually isn't) there's a strong chance that the star will fall into a binary system with our sun and the other star in highly elliptical orbits, which basically means if you leave the simulation going for more than a few hundreds or, if the effect is bad enough, tens of years, there won't be any stable orbits to speak of when you come back to it. Also, I'd say that any planet within 5-10 AU of the other star's passing have almost no chance of staying in the sun's gravitational grip; they'll be slingshotted out very easily, and if a planet comes within about 4 AU it pretty much has no chance.

About the "only able to set the aim point to 2 AU", depending on what you mean, I may or may not be able to help you.

Also, a lot of this applies no matter what, but some of it I'm not too sure about since you're using the encounters tab, and I don't know if that actually considers how much the sun will pull on the other star and vice versa, but if it does consider that then a lot of this post can be ignored, I just don't know for sure, since I don't use the encounters creator much, if I want to do that sort of thing I usually do it manually so that it's more natural (aka the angle it comes in from isn't 10.00 degrees, it might be 11.483 or something, but the chances of such an event is extremely rare (on its own is still rare especially with how spread out and slow moving the stars around the sun are, but having a specific angle like that is much less likely since there are many more possibilities that aren't a regular number) but if you're looking for extreme accuracy, I suppose having the angle and other parameters set exactly will make it more so.

emarksmi

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Re: Planning for my next long run simulation
« Reply #5 on: January 26, 2017, 02:40:00 PM »
Good points and thoughts.  I've pretty much given up on using the Encounters Tab (or Launch Tab for that matter) to make this happen.  I simply can't find a way to get the second star to pass far enough away from the Sun. 

My current plan is to use a star in a VERY long orbit and then bump the incoming velocity so it is above escape velocity.  It looks like I'm going to have to experiment a little to get this right.

As for the evolution during the encounter, I agree completely.  In fact, I'm thinking that any planet that is closer to the passing star than then sun is likely to be highly disrupted.  The same will go for the passing solar system.  IMO, that is the point of running something like this.  Run an encounter between two solar systems and see what happens.  The reason I like to start with ours is that we are familiar with it and we can see what the effects were more easily.

Finally, I agree that the initial conditions are somewhat arbitrary.  10 degree angle?  Highly unlikely but probably not substantially more or less likely than any other angle.  The idea is to set up an encounter that is plausible and has, at least in my quick assessment, the possibility of producing an interesting interaction.