COROT space mission ready to search out new planets and map the interior of stars

COROT may discover the first planets elsewhere that closely resemble the Earth in size and composition. The mission is led by the French National Space Agency (CNES) to which the European Space Agency (ESA) and several partner nations are providing a particularly strong international ‘flavour’.

While CNES is completing the preparation for the COROT launch, ESA and a large number of European scientists involved in the mission are eagerly waiting for this event to take place and for the first scientific results to arrive.

Professor Ian Roxburgh, of Queen Mary University London and the ESA member of the Scientific Committee, has been involved with COROT from its inception. He says “COROT is the first dedicated space mission to pursue both asteroseismology and planet-hunting, but the measurements required for both are essentially the same – high precision results on how the radiation from a star changes over time. A planet passing in front of a star can be detected by the fall in light from that star. Small oscillations of the star also produce changes in the light emitted which reveal what the star is made of and how they are structured internally. This data will provide a major boost to our understanding of how stars form and evolve. ”

COROT (pronounced ‘Coreau’) stands for ‘Convection Rotation and planetary Transits’. The name describes the scientific goals of the mission. ‘Convection and rotation’ refer to the capability of COROT to probe into stellar interiors studying the acoustic waves that ripple across the surface of stars (a technique called 'asteroseismology'). ‘Transit’ refers to the technique by which the presence of a planet orbiting a star can be inferred from the dimming starlight, caused when the planet passes in front of it. To accomplish its two scientific objectives, COROT will monitor about 120 000 stars with its 30-centimetre telescope.

COROT will lead a bold new search for planets around other stars. Since the discovery in 1995 of the first exoplanet, more than 200 other planets have been detected from ground-based observatories. COROT promises to find many more during its two-and-a-half-year mission, and to expand the frontiers of our knowledge towards ever smaller planets.

Many of the planets COROT will detect are expected to be 'hot-Jupiters'. An unknown percentage of the planets detected by COROT are expected to be rocky worlds, maybe just a few times larger than the Earth (or even smaller). If COROT finds these worlds, they will represent a new class of planet.

While it is looking at a star, COROT will also be able to detect 'starquakes', acoustic waves generated deep inside a star that send ripples across a star's surface, also altering its brightness. The exact nature of the ripples allows astronomers to calculate the star's precise mass, age and chemical composition and map the interior structure.

CNES is leading the mission and is partnered by ESA, Austria, Belgium, Germany, Brazil and Spain. CNES is responsible for the entire system and for the launch contract with the French-Russian company Starsem, who are providing a Soyuz launcher. The UK science funding agency, the Particle Physics and Astronomy Research Council (PPARC) funds Professor Roxburgh to participate in COROT.

The contribution of the other international partners range from the provision of hardware units, to ground stations, complementary ground-based observations of the targets to be studied by COROT, and the analysis of the COROT scientific data to come.

ESA is playing a crucial role in the mission. It provided the optics for the telescope, sitting at the heart of the spacecraft, and testing of the payload. Through this collaboration, a number of European scientists have been selected as Co-Investigators in open competition. They come from Denmark, Switzerland, the UK and Portugal. As a result of ESA’s participation in COROT, scientists from ESA’s Member States will also be given access to the satellite’s data.

ESA’s SOHO spacecraft has been making asteroseismology observations on the Sun, so comparing COROT’s data with SOHO will let scientists see how our parent star the Sun compares to other stars.

ESA plans to continue its search for Earth-like worlds in the second decade of the century with the launch of the Darwin mission. This flotilla of 4 or 5 spacecraft will take pictures of Earth-like worlds, allowing scientists to search for signs of life.