JWST Finds Exoplanet Covered in Deep Boiling Water; Could This Water World Harbor Life?

A few light years away from our Solar System, an exoplanet was found to be entirely covered with water. However, this water world cannot be easily compared to Earth since its deep ocean could be as hot as a pot of boiling water.

A Glimpse Into Atmospheric Mysteries

Experts discovered the strange planet after interpreting data collected using NASA's James Webb Space Telescope. Their findings are described in the paper "Possible Hycean conditions in the sub-Neptune TOI-270 d."

Armed with powerful tools, scientists explored the atmospheric makeup of TOI-270 d, a candidate hycean world. They used NIRSpec G395H, which covers the 2.7-5.2 micrometer range. In addition, they utilized the HST WFC3 spectrograph, which covers the 1.1-1.6 micrometer range. Professor Nikku Madhusudhan led the analysis, which revealed large signatures of methane and carbon dioxide in the atmosphere of TOI-270 d.

The discovery is part of multiple JWST GO Programs 2759, 3557, and 4098, using joint forces of NIRSpec, NIRISS, and MIRI instruments. The rare occurrence of simultaneous exoplanet TOI-270 b and d transits provided the cosmic spectacle. During the observation window, the instruments unleashed 5.3 hours of exposure time.

Strangely, no trace of ammonia was found in the exoplanet. The evidence for the ocean in TOI-270 d is based on the absence of this compound. Basic chemistry predicts that ammonia should naturally occur in a hydrogen-rich atmosphere.

However, astronomers also consider ammonia to be highly soluble in water. This compound would be depleted in the atmosphere if an ocean was present below. The experts interpret TOI-270 d as a hycean world with a water ocean under a hydrogen-rich atmosphere.

Aside from water, the astronomers also found evidence of carbon disulfide in the exoplanet. This discovery is linked to biological processes here on Earth. Still, researchers emphasize the need for caution when determining life's potential. Other scientists not involved in the latest study called for further observations to refine their understanding of the atmosphere and the likelihood of an ocean in TOI-270 d.

Exploring TOI-270 d opens new avenues for understanding exoplanets and the potential for habitability beyond our solar system. It challenges our perceptions as we are invited to imagine distant worlds vastly different from our own.

READ ALSO: Exoplanet K2-18b Could Be a Hycean Water World That Supports Life, JWST Observations Reveal

Strange Hycean World

TOI-270 d is a distant sub-Neptune exoplanet in the TOI-270 planetary system. It is twice Earth's radius and about 70 light years away.

This planet presents a stark contrast in temperature since it is tidally locked, with one side facing its star and the other in infinite darkness. The day side reveals an extremely hot ocean, while the night could harbor more habitable conditions.

Meanwhile, its atmospheric pressure would be immense—tens to hundreds of times that on Earth, with hot steam rolling off the surface of the ocean. According to Madhusudhan, the ocean could be as hot as 212 degrees Fahrenheit (100 degrees Celsius) or more. At high atmospheric pressure, an ocean as hot as this could still exist as a liquid, although it is not clear if it would be habitable.

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