James Webb discovers habitable, icy exoplanet relatively close to Earth

“We may have found evidence of air on this world.”

Ice Ball Home

Using data from the James Webb Space Telescope, researchers have determined that an exoplanet named LHS 1140 b may be an icy waterworld with an atmosphere similar to Earth’s and even capable of supporting life.

The planet, previously thought to be a mini-Neptune—meaning it’s a gas dwarf similar to Neptune with a thick atmosphere of hydrogen and helium gas—is located just 48 light-years away from Earth and orbits its red dwarf star in the system’s habitable zone. That means it receives enough radiation from the star to technically allow for liquid water to exist.

However, recent data from the JWST suggest that LHS 1140 b is a rocky or icy, water-rich “super-Earth,” making it an even better candidate to search for extraterrestrial life than previously thought.

“This is the first time we’ve seen any evidence of an atmosphere on a habitable zone of a rocky or ice-rich exoplanet,” said NASA Sagan Fellow Ryan MacDonald, co-author of a paper accepted for publication in The letters of the astrophysical journalin a statement. “Detecting atmospheres on small, rocky worlds is a key goal for JWST, but these signals are much harder to see than those from the atmospheres of giant planets.”

“LHS 1140 b is one of the best small exoplanets in the habitable zone that can support a thick atmosphere. We have found possible evidence of air on this world,” he added.

Ocean rose

First discovered in 2017, the potentially habitable exoplanet, which is more than six times the mass of Earth, has already intrigued scientists due to its proximity to the solar system. The latest findings only add to the excitement.

“Of all the currently known temperate exoplanets, LHS 1140 b may be our best chance to one day indirectly confirm liquid water on the surface of an alien world outside our solar system,” lead author and doctoral student Charles Cadieux of the Université de Montréal said in a statement. “This would be a major milestone in the search for potentially habitable exoplanets.”

It’s too early to say whether LHS 1140 b is a super-Earth cloaked in nitrogen, like our own atmosphere. But observations suggest that somewhere between 10 and 20 percent of its mass is water, meaning it could be a giant snowball or an ice cube with a subsurface ocean.

The researchers’ analysis also suggests that the atmosphere could be nitrogen-rich, supporting such a hypothesis. If that were the case, the exoplanet would have a 2,485-mile ocean on its surface, at a pleasant 68 degrees Fahrenheit.

“This is our first tantalizing glimpse of an atmosphere on a super-Earth in the habitable zone,” MacDonald said. “While we need more JWST observations to confirm the nitrogen-rich atmosphere and to search for other gases, this is a promising start.”

More about super-Earths: Astronomers discover potentially habitable planet

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