Like marbles rolling on a tabletop, the planets of our solar system all orbit the Sun in the same plane. That layout supports the leading ideas of how planetary systems are born -- from thin disks of gas and dust encircling their parent stars.
These ideas are based on a sample of just one system -- our own. But astronomers are beginning to look at other systems to see if they're laid out the same way.
One team of astronomers, for example, is using Hubble Space Telescope to plot the layouts of four systems with known planets. Hubble can measure tiny changes in the position of the parent star caused by the gravitational pull of its planets. When combined with observations from ground-based telescopes, that reveals how the systems are laid out.
Team leader Fritz Benedict says that one of the targets is a star known as Gamma Cephei:
BENEDICT: Gamma Cephei is an interesting case because it is two stars orbiting a common center of mass, and one of the stars has a companion. It's suspected to be a planetary mass companion. This is a planetary system that is truly unlike our own because there are two suns involved rather than just one, but we still want to know, is the planet orbiting one of these stars in the same orbital plane as the two stars that are orbiting together.
Gamma Cephei is in the north tonight. If you follow the line of the two outer stars in the bowl of the Big Dipper, the first moderately bright star you come to is Polaris, the North Star. The next one is Gamma Cephei -- a system that may be about to put its cards -- and its planet -- on the table.
Script by Damond Benningfield, Copyright 2009
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