Fictional multiple star system question

[EternalFrustration]

A question for the astrophysics experts:
I'm trying to develop a fictional quintuple star system, vaguely inspired by Xi Scorpii. Stars A and B revolve around each other, Star C revolves around the AB barycenter. Stars D and E revolve around each other. The ABC group and the DE group then revolve around each other.
My question is: how do I calculate the orbital periods? I've found several websites that will let you plug in values in Kepler's Third Law and spit out your remaining variable, but they all seem to be geared toward a planet orbiting a sun, or a moon orbiting a planet.
Could any of you please point me in the right direction of how to figure it out?
Thank you,
P

 

[RisingFury]

For A and B, assume that B is orbiting A and calculate using Kepler's law.
For C around AB, assume that the barycenter of A and B is the center of an object with a mass of A + B. Then use that to calculate orbital period.

For D and E, do the same as A and B. To get the orbital period of DE, assume that the barycenter of DE orbits the barycenter of ABC. Add the masses and plug it in.

This isn't 100% accurate, but it will be close enough. If a system like this is stable, then the orbital periods won't fluctuate too much. If it's unstable, then orbital periods might fluctuate to the point where they're constantly changing and orbital period is a function of time, not a constant.

 

[jedidia]

Plus, you might get some frustration from the fact that Orbiter doesn't really support systems with multiple stars. You'll have to define a star with size 0 at the barrycenter, and make the three stars planets. Expect unavoidable problems with lighting.

 

[sorindafabico]

Also, you can make a ficional rogue planet system, without a star. :idea:

Bring some light bulbs and a nuclear reactor in your Delta Glider.

 

[EternalFrustration]

Plus, you might get some frustration from the fact that Orbiter doesn't really support systems with multiple stars. You'll have to define a star with size 0 at the barrycenter, and make the three stars planets. Expect unavoidable problems with lighting.

Full disclosure: This is actually for Celestia, I know there's no way I'd ever have the skills to be able to model this in Orbiter

 

[jedidia]

Ah ok, no problem then. Making star systems for Orbiter isn't really more difficult than for celestia, it's just that multiple star systems aren't supported.

 

[spaceranger]

You could pick up Universe Sandbox and use it to test out your math. It's a fun little program!
http://universesandbox.com/

 

[Radu094]

If a system like this is stable..

I've been woking on accretion disk simulations for the last couple of years. Granted, it isn't a profesional simulator, but it's a pretty solid piece of engineering. After some "billion" simulations I've never encountered a stable quintuple, not without manually tinkering with the system anyway.

While there is nothing in theory that eliminates them,it seems to me the requirements are quite unprobable:

You need to have 5 nucleii (rare enough) that are big enough to eventually start fission, however:
- if they form too close to eachother they will perturb eachother's accretion disk to the point of stealing one-another's gas, so you usually end up with 1 large star and perhaps 3 - 4 dwarfs or gas giants
- if they actually are far enough to be stable and develop they drop out of each-other's SOI and wander off as independent systems

I guess there could be a sweet-spot inbetween, but then again it might be the two requirements overlap and there is no possible input to produce such a system

Binary systems, not a problem. Tertiary can happen every now and then if the conditions are right, even a couple of quadruples, but no quintuple so far..