The effect of 2 suns

[andrick]

Hi there, I was wondering what the effect 2 suns of equal dimensions would have on a planet that on a planet caught between the two pulls.<br /><br />I have 2 theories on this.<br /><br />1. the planet would circle both suns moving in a figure 8 type orbit.<br /><br />2. the planet would orbit 1 sun, but with each revolution the gravitational pull of the other sun would pull it closer to itself. The planet would thus be caught in a type of tug-a-war by the two suns until one gravitational pull would be dominant or the world was pulled apart.<br /><br />I was just wondering as I am thinking of turning my hand to some science fiction writing and would like to know correct theory to go by. <br /><br />I am in no ways an expert in astronomy and felt I should go to the people that know.

 

[thalion]

1.) IIRC, a figure-eight orbit would be highly unstable, and probably very unlikely in a real-word instance.<br /><br />2.) In this scenario, I'm thinking it's more likely that your planet will be ejected from the system, collide with one of the two suns, or get flung out into an eccentric orbit around both members rather than get pulled apart. For something as large as a main-sequence star, the variation in tidal pull across a planet's diameter is probably not that great--if anyone is more well-informed though, feel free to correct me.<br /><br />You may find these links useful:<br /><br />http://www.arachnoid.com/gravitation/small.html (A gravity simulator that is a lot of fun, and even has your figure-eight orbit)<br /><br />http://www.burtleburtle.net/bob/physics/eight.html (This site is also a lot of fun, and has Java simulations of exotic orbits that the webmaster has done himself--it's worth browsing through.)<br /><br />http://janus.astro.umd.edu/AW/awtools.html (Go to the three-body integrator section. The graphical output can be a little hard to interpret, but this site is, IMO, invaluable for serious simulation.)<br /><br />Best of luck, from another aspiring SF writer...

 

[docm]

Since many binary or trinary star systems have members that are are quite far apart it's far more likely that at least one would have its own planetary system. <br /><br />In point of fact an exosolar planet in a trinary system has already been discovered, the HD 188753 system, and the discoverers are calling such worlds "Tatooine planets";<br /><br />Link.... <div class="Discussion_UserSignature"> </div>

 

[3488]

You might find this interesting.<br /><br />Views from Alpha Centauri.<br /><br />Views from Sirius.<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>