New model aims to demystify ‘steam worlds’ beyond our solar system

For astrobiologists, the search for life beyond our solar system could be likened to where one would look in a vast desert—essentially, where there’s water. And it turns out that one of the most common types of exoplanet observed in planetary systems beyond ours has a size and mass that indicate a water-rich interior. They are categorized as “sub-Neptunes” because their size and mass are between that of Earth and Neptune.