Figure-eight orbit in a binary system...

[heyo]

Would this be theoretically possible? If there was a planet in with a binary system of two stars at an arbitrary distance apart, could it have a figure-8 orbit? Maybe where it would go around each star in an ecentric orbit enough to be captured by the other star into another ecentric orbit, which would fling it back to it's partner the next time around?<br /><br />Would a setup like this be stable?<br /><br />Just something I've been curious about. I also wonder what the suns would look like in the sky throughout the "day".. seems like the suns would both be in the sky most of the time and then alternately eclipse each other.<br /><br />Heyo

 

[Saiph]

Correct, while this orbit can occur, it cannot last for long.<br /><br />It's akin to balancing a pencil on it's tip. It can be done, it can stay that way for a bit, but it will fall at any disturbance.<br /><br />Any planet that does such an orbit will have it's trajectory altered to one of three cases: 1) Orbit a single star in a much closer orbit. 2) Orbit both stars at a distance. 3) Be ejected entirely. <div class="Discussion_UserSignature"> <p align="center"><font color="#c0c0c0"><br /></font></p><p align="center"><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">--------</font></em></font><font color="#999999"><em><font size="1">----</font></em></font><font color="#666699">SaiphMOD@gmail.com </font><font color="#999999"><em><font size="1">-------------------</font></em></font></p><p><font color="#999999"><em><font size="1">"This is my Timey Wimey Detector.  Goes "bing" when there's stuff.  It also fries eggs at 30 paces, wether you want it to or not actually.  I've learned to stay away from hens: It's not pretty when they blow" -- </font></em></font><font size="1" color="#999999">The Tenth Doctor, "Blink"</font></p> </div>

 

[thalion]

Here are some groovy Java simulations of various figure-eight orbits:<br /><br />http://www.burtleburtle.net/bob/physics/eight.html<br /><br />Here is another:<br /><br />http://www.arachnoid.com/gravitation/small.html<br /><br />(select "Three Body Figure-Eight" from the pull-down menu)<br /><br />Realistically though, such orbits would be unstable and almost impossible to create naturally, IMO. Too many conditions would have to be perfect.

 

[Leovinus]

Apollo 13's flight path was just about a figure 8. They put themselves on the free return trajectory. Had it been tweaked a bit, they wouldn't have re-entered but instead would have swung around the Earth. <div class="Discussion_UserSignature"> </div>

 

[heyo]

<i>Apollo 13's flight path was just about a figure 8. They put themselves on the free return trajectory. Had it been tweaked a bit, they wouldn't have re-entered but instead would have swung around the Earth. </i><br /><br />Interesting.... but I ebt if they did, they'd be in an eccentric orbit and might swing out by where the moon was, but it'd have moved so they'd probably just keep on cruising back around towards Earth (or collide with the moon)<br /><br />Heyo<br /><br />

 

[igorsboss]

I was playing around with the simulator at http://www.arachnoid.com/gravitation/index.html, and found an interesting orbit. <br /><br />It is probably unstable ad impossible, but it's beautiful anyway. It looks like a butterfly. as the two attractors play catch with each other<br /><br />* Start with the 3-body figure-8,<br />* Click "Data"<br />* For the second body, change x=1550.0 to x=2464.0<br />* Click "View"<br />* Click "Go"<br />* Optionally, check "Lines"<br />