Jupiter and Saturn's siblings

The planets described in this study were found with a technique called "microlensing," in which the gravity of the star and planet act as lenses, magnifying the light from a background star. By studying the complex patterns of the magnified light as the planetary system moves in front of the distant background star, scientists can determine the properties of the planets and their star. Only six planets have been discovered using the microlensing method. The discovery of this system from such a small sample of detections may indicate that solar systems like ours are common.

Researchers have discovered two new planets outside our solar system, each with a mass less than that of Jupiter. The planets are orbiting a star about half the size of our sun.

Although there has been a flurry of extrasolar planet discoveries in recent years, most of the planets have been massive bodies much larger than the giants of our own solar system.

But, the new planets, along with their sun, are more like the planets in our own solar system in terms of their size and the distances between their orbits, say B. Scott Gaudi of Ohio State University and his colleagues, who come from 11 different countries.

The planets were detected with a technique called gravitational microlensing, where starlight is bent or warped by the gravitational pull of the planets. They are the fifth and sixth to be discovered by microlensing. In the future, this technique may reveal other planetary systems similar in scale to our solar system throughout the Milky Way.

These findings appear in the 15 February 2008 issue of the journal Science.

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