Astronomers declared last year that they had spotted water vapor in the atmosphere of an exoplanet dubbed as K2-18b with temperatures conducive for living. However, the large size of the planet made the possibility uncertain.
The exoplanet K2-18b is intriguing for scientists and it could broaden the range of exoplanets astronomers target for potential life.
In 2019, astronomers peered into the atmosphere of the exoplanet and discovered both water vapor and possibly livable temperatures.
A study suggested that the Super-Earth, 124 light-years away from our planet, could be a habitat to an ocean world.
According to Nikku Madhusudhan from Cambridge's Institute of Astronomy leading the study, "A central conclusion of our study is that the planet -- K2-18b -- is potentially habitable. There is a reasonable chance that the planet hosts a large ocean underneath the atmosphere at pressures and temperatures similar to those in the Earth's oceans."
The University of Cambridge team used the mass, radius, and atmospheric data of the exoplanet K2-18b. They identified that it is possible for the planet to host liquid water at habitable conditions beneath its hydrogen-rich atmosphere.
124 light-years away in the constellation Leo and about eight times the size of Earth, it is the right distance from its star to conceivably harbor life.
The exoplanet was discovered in 2015 and is one of the hundreds of Super Earths - planets bigger than Earth but smaller than Neptune.
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This distant world is one of the more than 4,000 exoplanets that have been discovered to date.
It rose to fame last September when two different teams announced in the journal Nature Astronomy the discovery of water vapor in the exoplanet's atmosphere.
K2-18b is an exoplanet orbiting a red dwarf star K2-18 situated in the middle of the habitable zone -- not so hot that liquid water would evaporate from the surface, and not so cold that water can freeze.
Madhusudhan said, "Water vapor has been detected in the atmospheres of a number of exoplanets but, even if the planet is in the habitable zone, that doesn't necessarily mean there are habitable conditions on the surface."
"To establish the prospects for habitability, it is important to obtain a unified understanding of the interior and atmospheric conditions on the planet -- in particular, whether liquid water can exist beneath the atmosphere."
The research team has elucidated the composition of both the atmosphere and interior of K2-18b.
Despite the size of K2-18b or it being a mini-Neptune, its hydrogen envelope is not too thick and the water layer could have the right conditions to support life.
A large amount of water vapor is also present in the atmosphere, along with lower-than-expected levels of ammonia and methane.
Aside from having the right temperatures, a living world requires an atmosphere with the right pressures to maintain life. A rocky interior for water is helpful too.
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