Kepler-11 b

Kepler-11b is an exoplanet discovered around the star Kepler-11 by the Kepler space telescope, a NASA-led mission to discover Earth-like planets. Kepler-11b is less than about three times as massive and twice as large as Earth, but it has a lower density (≤ 3 g/cm3), and is thus most likely not of Earth-like composition. Kepler-11b is the hottest of the six planets in the Kepler-11 system, and orbits more closely to Kepler-11 than the other planets in the system. Kepler-11b, along with its five counterparts, form the first discovered planetary system with more than three transiting planets—the most densely packed known planetary system. The system is also the flattest known planetary system. The discovery of this planet and its five sister planets was announced on February 2, 2011, after follow-up investigations.

==Naming and discovery== Kepler-11b is named in two parts. The first part of its name is derived from the fact that it orbits the star Kepler-11. As the discovery of Kepler-11b was announced simultaneously with those of other planets, Kepler-11b was given the designation b because it was the innermost of the six announced planets. The host star, Kepler-11, was named for the Kepler Mission that flagged it as host to several potential transit events under the name KOI-157. The Kepler satellite is a NASA-run space telescope that is tasked with the discovery of terrestrial planets that transit, or cross in front of, their host stars as seen from Earth. These transits cause fluctuations in the host star's brightness; these changes may suggest the presence of a planet, which can then be verified by follow-up observations.