Discovered a new type of exoplanet that would consist largely of water: ‘We expect a very thick atmosphere of vapor’

That system consists of 4 planets: Kepler-138b, Kepler-138c, Kepler-138d, and the newly discovered planet Kepler-138e through this research. Principal investigator Caroline Piaulet studied Kepler-138c and Kepler-138d with both the Hubble Space Telescope and the Spitzer Space Telescope. She discovered that planets may consist mostly of water. It would be, because the water was not detected directly.