The French space telescope COROT (Convection, Rotation, and Planetary Transits) was launched into a polar orbit by a Russian Soyuz rocket on December 27, 2006. COROT is 13 feet long, weighs 1,400 pounds, and has a 12-inch telescope. Its mission is to take repeated and precise measurements of the brightness of selected stars for five months.

Astronomers will look for oscillations, or wiggles, in the light from the stars. This technique is called asteroseismology. It can probe the stars’ interior structure and can detect small planets transiting, or crossing, the face of the star. Stars dim slightly when planets pass in from of them, blocking some of the stars’ light. The images will be unfocused, not sharp, which allows the stars’ brightness to be measured more accurately. The difference of only a few photons can be detected out of 10 million or so photons coming from a star every second.

COROT will be aimed toward the galactic center in the area of Serpens (the Serpent) located just north of Sagittarius (the Archer) and opposite the center toward Monoceros (the Unicorn), located between Canis Major (the Big Dog) and Canis Minor (the Little Dog.) COROT will image thousands of stars between the 12th and 16th magnitude. Magnitude is a measure of brightness. Astronomers expect to find hundreds of new exoplanets, many only a few times larger than Earth but too small to be detected by Earth-based telescopes. The larger U.S.-led Kepler mission scheduled to launch in 2008 will use the transit technique to look for Earth-sized planets.