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Far-distant planets similar to Jupiter, Saturn

By Washington Post
Published February 15, 2008

Researchers have discovered two planets in a solar system 5,000 light-years away that appear to be structured in some important ways like our own.

The planets are gas giants similar to but smaller than Jupiter and Saturn, and their relative sizes are also similar. In addition, they circle their star at a distance proportional to the distances of Jupiter and Saturn from the sun.

"This is the first time we've found a Jupiter-like planet in the same system as a Saturn planet," said Scott Gaudi of Ohio State University, lead investigator on the project. "There's reason now to believe there are probably many more solar systems like it."

The discovery, published today in the online edition of the journal Science, lends support to the long-held belief of many astronomers that many planets orbit stars in ways similar to our solar system. Most of the more than 260 planets discovered so far have orbited their suns far more closely than theorized, and the planets have been larger than expected.

Gaudi said that was most likely a result of the techniques used to search for the planets, techniques that work best at finding large planets that orbit close in. His group used a different method, called gravitational microlensing, that required collaboration with professional and amateur astronomers from around the world.

Using that technique, the two planets were discovered when the star they orbit crossed in front of a more distant star, as seen from Earth. For a two-week period from late March through early April of 2006, the nearer star magnified the light shining from the farther star by some 500 times.

Taking advantage of that magnification, astronomers were able to detect the planets as they appeared to cause their star to brighten slightly.

[Last modified February 15, 2008, 01:08:54]