From: "Mike Reynolds" <mike_reynolds_at_cec001-fa@cc.cranbrook.edu>
Subject: Binary stars
Date: Fri, 14 Nov 97 16:01:53 -0500
During one of my study hall classes some students starting using the Mars-navigator CD. They where exploring the Mars Global Surveyor portion, in particular the lesson Beyond the Solar System. The lab portion of this activity asked the students to try to stabilize the orbits of four planets as they circle the sun. You can change the mass of each planet, distance from the sun and starting velocity of the planet. By playing around with these options you are to try to get all four planets in nice elliptical orbits around the sun. Having done this they then set the mass of one of the planets to 10EE30. In other words a very large planet. The gravitational pull of this planet is so strong that it often pulls other planets into orbit around it. Most of the time it causes the other planets to be either launched, sling shot style, out of the solar system or crash into the sun. This scenario causes planets to orbit one way and then change directions. It can cause them to have very bizarre elliptical orbits which seem to be in constant change, but almost always end up launching a planet out of the solar system or into the sun. After trying unsuccessfully to achieve stable orbits we have come to an interesting conclusion. Many of the star systems in the galaxy are binary star systems, have two stars orbiting each other. This would be similar to our experiment with the giant planet. Since we are unable to get planets to achieve stable orbits, is it possible that the same would be true of binary star systems? We are drawing the conclusion that there would be no Earth sized planets in any of these binary star systems. They would have been either launched into deep space, swallowed by one of the parent stars or more likely never to have formed. Does anyone have any thoughts on this? Does anyone have any suggestions as to who might talk to about this? If you have the Mars Navigator CD, try the lesson yourself. We have been trying to get stable orbits for sometime and are still unsuccessful. It doesn't seem to matter where you start the big planet, the results are always the same. Try it. If nothing else my students got a kick out of watching the blue planet (Earth) get launched into the sun or out into deep space. Mike