Rich exoplanet system discovered

By Victoria Gill
Science reporter, BBC News

The researchers say the finding marks a new phase in the hunt for exoplanets

Astronomers have discovered a planetary system containing at least five planets that orbit a star called HD 10180, which is much like our own Sun.
The star is 127 light years away, in the southern constellation of Hydrus.

The researchers used the European Southern Observatory (Eso) to monitor light emitted from the system and identify and characterise the planets. They say this is the "richest" system of exoplanets - planets outside our own Solar System - ever found. Christophe Lovis from Geneva University's observatory in Switzerland was lead researcher on the study. He said that his team had probably found "the system with the most planets yet discovered".

The discovery could provide insight into the formation of our own Solar System "This also highlights the fact that we are now entering a new era in exoplanet research - the study of complex planetary systems and not just of individual planets," he said.

The research has been submitted for publication to the journal Astronomy and Astrophysics. Eso's High Accuracy Radial velocity Planet Searcher (or Harps) instrument was responsible for the discovery. Harps measures the wobble of a star; this gives a measure of how much it is being tugged on by an orbiting planet. "If there is one planet it will induce a little movement - the star will come towards us and move away," Dr Lovis explained to BBC News. "And what works for one [planet] works for many."

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