European astronomers discover forty-five new planets

by Rich Bowden - Jun 16 2008, 22:49

European astronomers have discovered 45 new planets in our galaxy including three Earth-size objects circling the star HD 40307.

Using the HARPS (High Accuracy Radial Velocity Planet Searcher) spectrograph at La Scilla Observatory in Chile, the team were able to estimate that around one third of stars in the galaxy were orbited by planets.

"Does every single star harbour planets and, if yes, how many?" asks astronomer Michel Mayor from Geneva Observatory. "We may not yet know the answer but we are making huge progress towards it."

The team found three planets orbiting a star similar in size to our own 42 light-years away from  Earth. One is  4.2 the mass of Earth, the second  6.7 times and the third 9.4 times.

While none of the planets are visible, they can be viewed using the special spectrograph at La Silla which measures a sun's "wobble" as the planets orbit.

"With the advent of much more precise instruments such as the HARPS spectrograph ... we can now discover smaller planets, with masses between 2 and 10 times the Earth's mass," said team member Stephane Udry, to Reuters.

Mayor said in a press statement he believed the discoveries were “only the tip of the iceberg,” adding: "The analysis of all the stars studied with HARPS shows that about one third of all solar-like stars have either super-Earth or Neptune-like planets with orbital periods shorter than 50 days."

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