The first images taken by the James Webb Space Telescope were released by NASA in July of 2022. The most common red dwarf stars are dimmer than rocky planets and will be searched for by the telescope. Astronomers will get a better understanding of the types of worlds that exist out there by completing the census of exoplanets. Astronomers are interested in the number of water worlds in our universe.

These are rocky planets that are larger than Earth but have a lower density, which means that volatiles like water make up a significant amount of their mass-fraction. Water worlds may be just as common as rocky planets according to a recent study. The case for exoplanets that are similar to icy moons in the Solar System could be strengthened by these findings.

The University of Chicago and the Institute de Astrofsica de Andaluca led the study. The results of their research were published in the journal Science. For the purpose of their study, Luque and Pallé analyzed the mass and radii of all 43 rocky exoplanets in the catalog that are in contact with M-type stars.

The distribution of the mean densities of the planets around M stars, in which the different types of planets (rocky planets, water-worlds, and mini-Neptunes) can be clearly distinguished. Credit: IAC

The data from NASA's TESS was combined with the data from the CAR MENES Telescope at the Calar Alto Observatory in southern Spain. They were able to get accurate measurement of the size and mass of these planets. A significant portion of the area had densities that were too light in relation to their size to be made up of rock.

They deduced that the exoplanets must be made of half rock and half water or other lighter molecule. Luque explained in a press release that.

“We have discovered the first experimental proof that there is a population of water worlds, and that they are in fact almost as abundant as Earth-like planets. We found that it is the density of a planet and not its radius, as was previously thought, which separates dry planets from wet ones. The Earth is a dry planet, even though its surface is mostly covered in water, which gives it a very wet appearance. The water on Earth is only 0.02% of its total mass, while in these water worlds it is 50% of the mass of the planet.”

The planets around M-type stars are usually tidally locked, meaning one side is facing toward the sun. Water on the planet's surface is likely to be in a supercritical gas phase at this distance. In this population, water is bound to the rock or in closed volumes below the surface, not on the surface. The conditions are similar to those found on icy moons in the outer Solar System.

Artist’s impression of a water world, where half of its mass consists of water. Just like the Moon, the planet is bound to its star by tidal forces and always shows the same face to its host star. Credit: Pilar Montañés

These planets are locked to their suns and may have liquid oceans on their sun-facing side but frozen surface everywhere else. Clarifying the existence of this class of exoplanet is the first confirmation of this new type of exoplanet. Water worlds that form beyond the so-called "snow line" in star systems can migrate closer to their star. The person said that.

“We have discovered that small planets orbiting this type of star can be classified into three distinct families: rocky planets very similar to Earth, planets with half their mass consisting of water that we call water worlds, and mini-Neptunes with extended atmospheres of hydrogen and/or helium. The distribution of sizes and densities of exoplanets is a consequence of the formation of planets at different distances from the star, and not of the presence or absence of an atmosphere.”

It is possible for an individual planet to fit into more than one category due to the uncertainties in the mass and radii of our measurement. The patterns of distinct, different compositions can be brought out by observing a population of planets.

The researchers plan to learn more about the internal structure of water worlds. This involves finding out where the water is stored and if the atmosphere is supercritical. Astronomers have observed icy moons with tenuous atmospheres and water Vapor and Oxygen. Exposure to solar radiation causes water to break into oxygen and hydrogen, which is lost to space

Artist’s impressions of two exoplanets in the TRAPPIST-1 system (TRAPPIST-1d & TRAPPIST-1f). Credit: NASA/JPL-Caltech

Thanks to its advanced suite of imagers and spectrometers, theJWST is ideally suited to conduct these surveys. A number of ground-based telescopes will be able to image exoplanets with the help of their coronographs and advanced spectrometers. Astronomers will be able to see the atmosphere and surface features of distant exoplanets with the help of these studies. Luque said that as well.

“It is also fundamental to understand if our discovery also applies to the populations of small planets around other types of stars. It is more difficult to measure the exact masses of small planets around larger stars, but the data should soon become available using the newest generation of ultra-stable spectrographs.”

The closest exoplanet beyond the Solar System will be included in future surveys. The rocky planet Proxima b is located in the same system as Proxima Centauri. Scientists have sought more information about its composition since it was confirmed. Scientists have speculated that some of the planets in TRAPPIST-1 may be wet eyeball planets.

The census of exoplanets is expected to reach tens of thousands in the coming years. The search for life beyond the Solar System is expected to accelerate with so many planets available for study.

The Instituto de Astrofsica de Canarias is a science journal.