Specialists mentioned last December 2022 that they were able to identify genuine extraterrestrial water worlds which are unlike any other bodies of water within the solar system. The Space Academy reports how such exoplanets slightly exceed Earth in terms of size. However, their density are in between that of a rocky planet like the earth and that of the gas-giant planets across the system.
These specialists think that such worlds could have oceans that go deeper than the earth-by a whopping 500 times.
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Two Worlds Discovered
EarthSky reports how the two words move in orbit of a red dwarf star labeled Kepler-138, which is located 218 light-years away in the direction of the Lyra Harp constellation. Scientists suggested the existence of such water worlds like this. While there have been clues in the past, these are the first specific worlds that offer strong evidence.
Findings were included in Nature Astronomy. The team was led by Caroline Piaulet from the University of Montreal's Trottier iREx (Institute for Research on Exoplanets).
Considering earth's water world nature, the planet may come to mind. However, these two exoplanets seemingly have oceans that are at least a thousand miles deep, which makes it around 500 times deeper compared to earth's average oceanic depth.
The astronomers were able to discover these waterworlds thanks to data from the now-retired Spitzer telescope as well as the Hubble telescope. Upon analyzing the data, the astronomers noticed something uncommon. Both exoplanets were seen to be slightly bigger than earth but they did not have density that was close to earth or any other rocky planets. Despite this, the planets were seen to be denser than the ice or gas giants across the outer system.
Björn Benneke, study co-author from the university, noted how they used to think of such planets as earth's scaled-up versions. For that very reason, such planets were referred to as super-earths. However, the team revealed that such exoplanets harbor significant differences in nature and that a huge fraction of their volume is made up of water. This serves as best proof for water worlds.
Water Worlds That Are Unlike Earth
Though their oceans are made up of water, the astronomers think that these bodies of water are not the same as earth's. The findings propose that such alien water worlds are remarkably warmer and have extremely high levels of pressure. Space Academy also reports the possibilities of an absent boundary to separate the ocean top and planet atmosphere.
The two planets also have a closer orbit to their respective stars. They are also not situated in habitable areas where temperatures could enable the existence of liquid water. This means that they have steamy and overheated atmospheres and that their liquid water has higher pressures in its depths.
The system of Kepler-138 also has two more planets. While Kepler-138 b is smaller and rocky, the Kepler-138 e is situated farthest from the star. It moves around the star for a span of 38 days and is located within the habitable zone's inner boundary. While astronomers are not yet sure about its size, the study proposes that its size exceeds that of Kepler-138 b. However, the planet is hard to study as its orbit does not transit at the star's front, unlike the other planets.
Generally, the findings reveal that not every super-Earth is rocky. There are some planets, such as the Kepler 138-c and 138-d that could be composed largely of water.
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