Another Saturn-like planet found

The data "wobble" that revealed the new planet

By Dr David Whitehouse BBC News Online science editor

Astronomers have found another planet outside our Solar System that has a mass less than that of our own Saturn.

This makes it one of the smallest so-called exoplanets ever detected.

It joins just four others that have masses smaller than Saturn's.

The new planet circles the star designated HD 76700, which is 194 light-years distant and is visible with a small telescope. The planet orbits HD 76700 every four days.

It is another example of a gas giant orbiting very close in to its parent, in this case at a distance of only six million kilometres (four million miles).

Researchers believe that even with the intense radiation it would experience at this location, the planet could still be stable in its orbit for billions of years.

The new discovery was made by astronomers involved in a planet search programme using the 3.9-metre Anglo Australian Telescope, which is surveying about 200 solar-type stars.

It was detected because of the motion induced in the parent star by the gravitation pull of the planet - the so-called "Doppler-wobble" technique.

Astronomers believe that this method cannot be improved in sensitivity much more to detect planets lower in mass than the one orbiting HD 76700.

Just over 100 exoplanets have now been discovered, but only five have a mass less than that of Saturn. These circle the stars HD 49674, HD 16141, HD 168746, HD 46375 and now HD 76700.