Illustration of CoRoT-7b. This is a super-Earth, discovered in 2009 orbiting the sun-like star CoRoT-7 in Monoceros. The planet orbits so closely - only 1/60th of Earth's distance from the Sun - that astronomers speculate that its surface is probably molten. It may have started as a much more massive gas giant, like Saturn, but gradually lost its gaseous envelope due to the radiation from its star. All that is left now is the original rocky core. Daytime temperatures on the planet may reach 2000 Celsius, but drop to -200C on the night side.