CoRoT-7b: The First Transiting Super-Earth Fully Characterized in Radius and Mass

In February 2009, the transit detection by the CoRoT satellite of CoRoT-7b, a planet as small as R = 1.7 R-Earth and closely orbiting a solar-type star, was announced at the CoRoT symposium in Paris. Here we present the arguments, largely based on follow-up observations from the ground, that leave practically no doubt on this detection and we give the last evaluation of the planet parameters. In addition, we show how the most recent results of radial velocity measurements with HARPS fully confirm the discovery and give now a firm evaluation of the mass of the planet, 4.8 M-Earth, and thus of its density which is equal to that of Earth, suggesting a similar composition dominated by silicates. Lastly, it is shown that a second planet, of only twice the mass of CoRoT-7b, is found on a slightly larger orbit, but still extremely close to the star. The discovery of the CoRoT-7 system is obviously an important milestone on the pathway to habitable planets.