A water world
The exoplanet TOI-1452 b is probably rocky planet like Earth, but its radius, mass and density suggest a world very different from our own.
Earth is essentially a very dry planet; Even though we sometimes call it the Blue Planet because about 70% of its surface is covered by ocean, water actually only makes up a negligible fraction of its mass less than 1%.
Water may be more abundant on some exoplanets. In recent years, astronomers have identified and determined the radius and mass of several exoplanets with the size of Earth and Neptune (about 3.8 times larger than Earth).
Some of these planets have densities that can only be explained if a large portion of their mass is made up of lighter materials that make up Earth's internal structure, such as water. These fictional worlds have been called "ocean planets".
"TOI-1452b is one of the best candidates for an oceanic planet we've found to date," Cadiaux said. "Its radius and mass suggest a much lower density than would be expected for an Earth-like planet originally composed of metal and rock."
"Our observations with the Webb telescope will be essential to better understand TOI-1452 b," said Doyn, who observed the concept of NIRISS, a component of James Webb. "As soon as we can, we will book time on the web to see this strange and wonderful world."