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Steam world
Exoplanet with atmosphere made mostly of hot water vapor
From Wikipedia, the free encyclopedia
A steam world is a type of exoplanet, with an atmosphere consisting of hot water vapor, or steam.
The first discovered steam world is GJ 9827 d which was characterized by the James Webb Space Telescope in 2024, led by a study team in the University of Montréal's Trottier Institute for Research on Exoplanets.[1][2] GJ 9827 d was first discovered by the Kepler Space Telescope back in 2017, and in 2023 the Hubble Space Telescope detected traces of water vapor in its atmosphere for the first time.
A particular characteristic of steam worlds is that they tend to be Sub-Neptune exoplanets.[2] Steam worlds are likely not capable of supporting life as we know it.[1]
