January 2, 2007, Baikonur Spaceport, Kazakhstan--COROT (Convection Rotation and planetary Transits), a space telescope designed to detect exoplanets orbiting around other stars, as well as to probe stellar interiors, launched on December 27 of last year. The telescope has a 30 cm aperture and was put into circular polar orbit around the Earth at an 827 km altitude, where it will remain for two and a half years. COROT is a French national space agency-led mission to which the European Space Agency and European partners are adding a strong international flavor.
For example, the COROT telescope includes four back-thinned frame-transfer CCD devices from e2v (Essex, England) that have been integrated into COROT's focal plane to capture images of stars.
The sensors will serve two purposes. First, a scientific study of the stars' seismic activity will be carried out. The 2048 x 2048 square pixel e2v devices will help COROT to examine "starquakes," or vibrations that change the brightness of stars. This will enable scientists to compute a star's age, size, and chemical makeup.
Second, COROT will search for indications of extrasolar habitable planets. The e2v imaging devices will detect the planets as they cross the discs of their parent stars, causing a dip in the brightness of the parent star, just as an eclipse of the sun darkens the Earth. However, COROT will be looking for events millions of times weaker than our familiar solar eclipse. The CCDs will sense the visible waveband.
To achieve its twin scientific objectives, COROT will monitor some 120,000 stars. In the decade since the first discovery in 1995 of an exoplanet (51 Pegasi b), more than 200 other such planets outside our solar system have been detected using ground-based observatories. Many of the planets COROT will detect are expected to be "hot Jupiters," or gaseous worlds orbiting very close to their suns. An unknown percentage of those detected are expected to be rocky planets, maybe just a few times larger than the Earth (or smaller, even). If COROT finds such planets, they will constitute a new class of planet altogether. Astronomers hope that between ten and forty rocky planets may be found.