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