[2] Kepler-11c orbits Kepler-11 every 10 days, and has an estimated density twice that of pure water.

[4] Kepler-11c and the other Kepler-11 planets were announced to the public on February 2, 2011, and was published in Nature a day later.

[5] Kepler-11 was flagged as home to a potential transit event by the satellite, and was given the designation KOI-157.

[8] With a density of 2.3 grams/cm3, Kepler-11c has a mass over double of that of pure water at 0 °C; it is also denser than all the Sun's gas giants, but less dense than any of its rocky planets.

Mercury, in comparison, orbits every 87.97 days at a distance of .387 AU.

[3] The Kepler team has said that Kepler-11b and Kepler-11c are probably composed mostly of water with a thin hydrogen and helium atmosphere.

[11] Support to the idea that the planets of this system formed ex situ and contain large amounts of H2O is provided by the radius of Kepler-11b, which can only be explained by the presence of a thin gaseous envelope.

However, since hydrogen and helium cannot survive for the age of the system bound to the planet because of photo-evaporation blow-off, the most likely alternative is the presence of a vapor atmosphere generating from its surface.