Cambridge astronomers identify 'Hycean' exoplanets that may soon yield signs of alien life

University of Cambridge astronomers have identified a class of “Hycean” exoplanets that could prove fruitful in search of alien life. According to a study, the researchers have said that signs of life beyond our solar system might be detectable within two to three years. They believe that there might be more promising possibilities after their recent work suggested that a “mini-Neptune”, more than twice the radius of Earth, might be habitable. 

The astronomers at Cambridge University identified a new class of habitable exoplanets, called Hycean planets (hot, ocean-covered and with hydrogen-rich atmospheres). The researchers said that the Hycean exoplanets are more observable than Earth-like planets. The mini-Neptune, known as K2-18b, is one such planet and there could be many more in existence, the astronomers said. 

“Hyceans are basically water worlds with hydrogen-rich atmospheres,” said Dr Nikku Madhusudhan, the lead author of the research from the University of Cambridge.

Dr Madhusudhan said that focusing on Hyceans could accelerate efforts to find life beyond Earth. He said, “within two to three years we may see the first biosignature detection if these planets host life”. He added that the James Webb space telescope could aid the search. 

‘Microbial life should be possible’

Further, Dr Madhusudhan went on to say that the small size of Earth-like planets relative to sun-like stars gave rise to weak atmospheric signatures, making it difficult to detect signs of life. However, he went on to explain that Hyceans can be more than twice the radius of Earth and about 10 times the mass. 

He also said that they could be significantly hotter, with average atmospheric temperatures reaching almost 200 degrees Celcius. Madhusudhan explained that larger planets are not only more common than Earth-sized ones but also easier to find. It is also possible to detect their atmospheres without difficulty. 

The team said Hycean planets were defined as having a hydrogen-rich atmosphere, a rocky core that accounts for at least 10% of the mass of the planet, and a water layer accounting for up to 90% of the planet’s mass. The team added that any life on Hyceans would necessarily be aquatic, as the planets, by definition, would be covered by a water layer. 

“At the bare minimum, microbial life should be possible,” he said, adding that this was how life started on Earth.

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