Sub-Neptunes are a class of exoplanets that are smaller than Neptune but larger than Earth, typically defined as having a radius between approximately 1.5 and 2.5 times that of Earth. These planets are characterized by their densities, which suggest they may possess a significant atmosphere, possibly composed of hydrogen, helium, and other gases, along with a solid or liquid surface beneath. Sub-Neptunes are primarily found in close orbits around their host stars, often within regions where conditions may allow for the retention of atmospheric materials.
They are distinct from both terrestrial planets, like Earth, and gas giants, such as Neptune and Jupiter, representing an intermediate category that provides valuable insights into planetary formation and evolution. The study of Sub-Neptunes helps astronomers understand the diversity of planetary systems and the potential for habitability in various environments.
New research conducted by an international team of scientists from NCCR PlanetS, UNIGE, and UNIBE has revealed the existence of two distinct populations of sub-Neptunes, settling a long-standing debate in…