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Planet in ‘habitable’ zone may have oceans and possible sign of life, reveals Webb

Waters may be flowing on the surface of a colossal planet about 120 light-years from Earth, according to new evidence discovered by the James Webb Space Telescope.

The investigation with the space observatory, one of the most advanced astronomical instruments in operation, revealed that the exoplanet K2-18b may have some key characteristics of a planet that could support masses of water — and life.

Closely orbiting the cool dwarf star K2-18, the exoplanet lies within the star’s habitable zone, or Goldilocks [“Cachinhos dourados”], and is 8.6 times the mass of Earth. An analysis of Webb’s observations found that the planet has abundant methane and carbon dioxide in its atmosphere.

The presence of these carbon-bearing molecules, along with the scarcity of ammonia, could indicate a hydrogen-rich atmosphere surrounding an oceanic world, according to one study. Press release from NASA.

Carbon is considered the foundation of life forms in the land.

The Hubble Space Telescope initially detected evidence of water vapor in the exoplanet’s atmosphere. The discovery, described in a September 2019 studyhelped scientists locate K2-18b for further study.

The Webb telescope, which can detect infrared light invisible to the human eye, looked for exactly which elements are present in the planet’s atmosphere.

And the latest observations of the planet also suggest that a very special molecule, called dimethyl sulfide, could be present on K2-18b.

On Earth, dimethyl sulfide “is produced only by life”, according to NASA. “Most of the DMS in Earth’s atmosphere is emitted by phytoplankton in marine environments.”

No guarantees

Researchers are not openly suggesting that K2-18b is teeming with alien life. More research is needed to confirm the presence of dimethyl sulfide, astronomer Nikku Madhusudhan, professor of astrophysics and exoplanetary sciences at the University of Cambridge, said in a statement.

Madhusudhan is the lead author of a new scientific paper describing the findings that has been accepted for publication in The Astrophysical Journal Letters .

And even if scientists corroborate the presence of the chemical compound, this does not guarantee that life forms exist there.

But this new evidence expands scientists’ understanding of exoplanets similar to K2-18b.

Warm ocean worlds

Findings about its atmospheric composition suggest it could be a “Hycean exoplanet,” a theoretical type of exoplanet that is hot but covered by oceans and has a hydrogen-rich atmosphere.

Where there are liquid oceans, there is potential for life — but researchers are still not sure whether these Hycean planets can support life. One August study published in The Astrophysical Journal, for example, suggests that they would experience an overwhelming greenhouse effect.

There are still no confirmed Hycean exoplanets. And there is no planet like K2-18b in our own solar system, and that makes planets like it “poorly understood,” according to NASA.

The “nature of their atmospheres is a matter of active debate among astronomers,” the space agency said in a press release.

But researchers involved in analyzing these recent observations of K2-18b have emphasized that it is essential to continue unraveling its mysteries.

“Our ultimate goal is to identify life on a habitable exoplanet, which would transform our understanding of our place in the universe,” said Madhusudhan. “Our findings are a promising step toward a deeper understanding of the Hycean worlds in this quest.”

Researchers plan to continue using the Webb telescope to study the distant planet and try to further validate the new findings.

“These results are the product of just two observations of K2-18 b, with many more on the way,” astronomer Savvas Constantinou, a PhD student in astrophysics at the University of Cambridge and co-author of the latest study, said in a statement.

“This means that our work here is just an initial demonstration of what Webb can observe on habitable zone exoplanets.”

Source: CNN Brasil

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