The French-led CoRoT space telescope discovered the rocky exoplanet CoRoT-7b. The mission detected the planet by recording the tiny, repeated dimming that occurred whenever it crossed in front of its host star, CoRoT-7.
CoRoT—short for Convection, Rotation and planetary Transits—was a joint French space mission launched in 2006. It was the first spacecraft dedicated to finding transiting exoplanets and also studied stellar vibrations, helping astronomers investigate the interiors of stars.
CoRoT-7b was announced in February 2009 after observations made from late 2007 into early 2008. Its radius was measured at about 1.58 times Earth’s, while follow-up radial-velocity work supplied a mass estimate. Together, those measurements indicated a dense, rocky world rather than a gas giant.
A common mix-up is to credit Kepler, which later found many small exoplanets, including Kepler-10b. CoRoT-7b instead belongs to the earlier generation of discoveries that demonstrated space telescopes could detect potentially terrestrial planets around other stars.