New planet discovery announced

Thursday 24 July 2008

The discovery of a new planet around the same size as Jupiter was announced today (24 July 2008) at an international astronomy conference at the University of St Andrews.

The discovery of the planet, named CoRoT-Exo-4b, was made by the European team behind the CoRoT space mission.  Slightly larger than the sun, the new planet takes 9.2 days to orbit its host star, one of the longest orbiting periods of any transiting planet ever found.

The research team, led by the French space agency CNES, were surprised to find that the star is rotating at the same pace as the planet’s orbit, since they presumed it too low mass and too distant from its star to have had much effect on its rotation.

Dr Suzanne Aigrain, from the University of Exeter, who led the analysis of the photometric data, spoke of the finding at the St Andrews event.  She said, “We don’t know if CoRoT-Exo-4b and its star have always been rotating in synch since their formation about 1 billion years ago, or if the star became synchronized later. CoRoT will no doubt find many more transiting planets, and by systematically measuring their host stars’ rotation periods we will gain valuable insight into how stars interact with their planets.”

Launched in December 2006, CoRoT is the first space mission designed to search for extra-solar planets. The satellite uses transits, the tiny dips in a star’s flux when a planet passes in front of it, to detect and measure planets. This is backed up by extensive ground-based observations. Because it is outside of the Earth’s atmosphere, which distorts the light coming from distant stars, the satellite should be able to detect planets almost as small as our Earth. Because of CoRoT’s continuous coverage over several months, the research team was able to track variations in the host star’s brightness between transits. To deduce its rotation period they monitored dark spots on its surface rotating in and out of view.

St Andrews’ astronomer Dr Martin Dominik commented, “Within less than 15 years, the count of planets orbiting stars other than the sun has risen from none to over 300. Some of these detections carried surprises that led to shake-ups of our understanding about the way planets form. As the first space-based mission searching for extra-solar planets, CoRoT has now demonstrated its capability for looking into planet-star interactions. The new findings provide reason for the scientists currently gathering in St Andrews to revise their theories – again.”

“Cool Stars, Stellar Systems, and the Sun”, held from Monday 21 July until Friday 25 July at the University of St Andrews, is being attended by around 350 international astronomers. The conference is the 15th in a long-standing series that has run since 1980, and is being held for the first time in the UK.





Notes to editors



CoRoT is primarily a mission of the French space agency CNES (Centre National d’Etudes Spatiales), with contributions from Austria, Belgium, Germany, Spain, Brazil and the European Space Agency. The ground-based follow-up of the CoRoT detection was done with the spectrographs SOPHIE on the 180cm telescope at the Observatoire de Haute Provence (France), HARPS on the 3.6m telescope at La Silla observatory (Chile) and UVES on the 8.2m Very Large Telescope at Paranal observatory (Chile), the 1m telescope at the Wise Observatory in Israel, the 1m Euler telescope at La Silla, and the 3.6m Canada-France-Hawaii telescope.






For further information contact:




  – Dr Suzanne Aigrain (University of Exeter): 07786 245 237




  – Dr Martin Dominik (University of St Andrews): 0777 764 2564




  Exeter Press Office – Sarah Hoyle, 01392 262062 / 07989 446920, [email protected]












Caption: Artists impression of the satellite CoRoT in orbit around the Earth.  Credit CNES.





Issued by the Press Office, University of St Andrews
Contact Gayle Cook, Press Officer on 01334 467227 / 462529, mobile 07900 050 103, or email [email protected]
Ref:  Corot planet 240708
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