New Class of Habitable Exoplanets very Different from Earth Discovered

Astronomers have found that there is a new class of exoplanets that may have suitable conditions for life, although they do not seem very domestic to us. They are saying their Hycean planet. These are hydrogen-dense atmospheres with very different conditions from the ocean world, mass, temperature, and the Earth. According to a report published in The Astrophysical Journal, members of this new class are both larger and warmer than Earth but have the right conditions to have oceans.

And those oceans can support life forms, as found in the most extreme ocean environments on Earth. Lead researcher Dr Nikku Madhusudhan from Cambridge’s Institute of Astronomy, said in a statement, “Oceanic planets open up entirely new paths in search of life elsewhere.”

The discovery of the exoplanet K2-18b and the discovery of water in its atmosphere inspired the team to explore some giant planets as life-supporting Earths. These are super-Earths or mini-Neptunes (depending on size) but are in a wide range of dense hydrogen atmospheres. They may also have a burning atmosphere. But maybe life finds a way around all this.

The team compresses the numbers and works out that the planets, with a 2.6 times radius of Earth and an atmospheric temperature of 200 ° C (392 ° F), may still have oceans that would be habitable for certain organisms. Even tidal planets, which have fixed starlight on one side, may still have habitable regions. But being a Hycean planet is not just about size and temperature. The structure of the atmosphere is also important. The atmosphere of an oceanic planet should have traces of other compounds besides hydrogen.

These include oxygen, ozone, methane, nitrous oxide, methyl chloride, dimethyl sulfide. Those molecules can indicate life. Madhusudhan added, “Basically, when we are looking for these different molecular signatures, we have focused on Earth-like planets, which is a reasonable place to start.” “But we think the Hycean planets offer a much better chance of finding several trace biosynthesis.” 

Exoplanet K2-18b will be monitored by Hubble’s successor JWST after its launch in October. Atmospheric analysis can actually reveal some interesting molecular signatures. Their large size and high temperature make it easy to detect atmospheric signatures. “It’s exciting that the existence of habitable conditions on Earth can be different from Earth,” said Cambridge co-author Anjali Piet.