Celestia Forums

I've completed the (fictional) Quad system described on this thread. The purpose of this was really just to test out the barycentre orbits in 1.5.0 (see instruction on this thread to get a recent compiled version for Windows, thanks to phoenix). This still works in 1.4.1, you just won't be able to see the star orbits though.

Download the quad.stc and quadlimit.ssc files from these links:

http://www.evildrganymede.net/art/celestia/quad.stc
http://www.evildrganymede.net/art/celes ... dlimit.ssc

Then go to QuadABCD. Make sure planet orbits are turned on (star orbits around barycentres are currently shown as planet orbits), as well as comet orbits, spacecraft and asteroid orbits and their labels. Make sure comet tails are turned off though.

Zoom out and you'll see the star orbits and a bunch of other orbits around them. (All non-star orbits are circular, since they're just there to show boundaries in different colours). These other orbits represent the limits at which planets can form, calculated using this paper: http://www.astro.uwo.ca/~wiegert/preprints/pp5.html

If you head over to the QuadAB barycentre, the green (comet) orbits around that represent where you can find planets - within the limitS1 and limit S2 orbits, and beyond the limitP.

Beyond that, I treated the AB binary as a single star with a mass equal to the combined mass of the two stars, and then used C (Quad3) as the second star in a larger binary and recalculated the limits. This yields the brown (asteroid) orbits ABlimitS1, ABlimitS2, and ABlimitP. Planets can't form around the binary beyond ABlimitS1 or around Quad3 beyond ABlimitS2, and planets can only be found beyond ABlimitP if they're orbiting all three stars. So there's a 'ring' around the binary in which you can find planets.

Going further out, the grey (spacecraft) orbits are the same thing for ABC. Here I've treated Quad1,Quad2, and Quad3 as a single star and used Quad4 as the second star in the binary for calculation purposes. ABClimitS2 is obviously the limit beyond which you can't find planets orbiting Quad4, but I'm a bit stumped as to what ABClimitS1 actually means and whether that restricts the placement of worlds in any of its 'sub-limits'.

Anyway, I thought I'd throw it out there, it's another handy way to use Celestia as a visualisation tool (customisable orbit colours would be nice though, as would some way to shade zones within/beyond/between orbits somehow). If nothing else this might give people an idea of where to find planets in multiple systems...

Note that this is an entirely fictional system, built using a realistic system generator I'm working on. But I am using ongoing research and papers to make things as realistic as possible.

Hm, 50 views and no comments? Maybe a screenshot might pique the interest.

I fear most people's eyes glazed over while reading the whys and wherefores

All of your orbits and limits currently are co-planar. I suspect the situation gets a lot more "interesting" if there are inclined orbits and the regions are shown as 3D surfaces

If you haven't already, you might want to mention what you're doing somewhere that they discuss stability and habitability zones. Unfortunately, it seems that public places are hard to find

That's a neat system and fun to watch.

I think your limits would be better visualized with a cmod showing the limits. Perhaps the size of the cmod for the ssc could be autogenerated by your system generator. Even better (I'm brainstorming) a flat sheet cmod with orbit zones (colored like you want) or even habitable zones, or a zones cmod in general, you could create different colors to represent different zones... All this, rather than orbits to show boundaries...since you always have to define some object in that orbit (don't like that)... Your cmod could even show the field dropping off to the square of the distance, maybe rings that get dimmer by half each time and a final circle indicating the extreme like your limit orbit.

Also, what's up with the comets?

Unfortunately I have no experience with CMODs, and my program is currently only outputting text (I had to manually create the ssc/stc files here. Maybe once it's done I can have the program output those though). But it's an idea at least.

And uh, what do you mean "what's up with the comets"? Are they doing something odd? I just used comet, asteroid, and spacecraft orbits to show the limits because they're different colours - if you're seeing actual comets then you should turn off the comet tails in the render options - the objects on the comet orbits are just there as placeholders so the orbits render, they're not real comets .

selden wrote:I fear most people's eyes glazed over while reading the whys and wherefores

Well I did wonder if I should post this in P&A...

All of your orbits and limits currently are co-planar. I suspect the situation gets a lot more "interesting" if there are inclined orbits and the regions are shown as 3D surfaces

Yeah, I don't know how inclinations vary within multiple systems. I'm assuming that at least if the stars are close to eachother then they'll be roughly coplanar. Distant stars might be more inclined though.

If you haven't already, you might want to mention what you're doing somewhere that they discuss stability and habitability zones. Unfortunately, it seems that public places are hard to find

Finding anywhere that scientists actually talk about science is hard enough... it seems the only way to get people to talk about what they do is to actually email them, and then you end up having very slow conversations over weeks when they get round to replying...! I might send this to the author of the paper though.

Malenfant wrote:And uh, what do you mean "what's up with the comets"? Are they doing something odd? I just used comet, asteroid, and spacecraft orbits to show the limits because they're different colours - if you're seeing actual comets then you should turn off the comet tails in the render options - the objects on the comet orbits are just there as placeholders so the orbits render, they're not real comets .

Ah, gotcha. I did have tails turned on.