A WATERY ‘super-Earth’ roughly 50 light-years away may bear the conditions to host life.
LHS 1140 b is an exoplanet orbiting a red dwarf star in the constellation Cetus. It falls in the star’s habitable zone, or the region with temperatures supporting liquid water.
Now, a team of scientists has determined the planet may harbor an atmosphere and an ocean similar to those on Earth.
A paper published this week in The Astrophysical Journal Letters identified LHS 1140 b as one of the most promising candidates with the conditions to support life.
“Of all currently known temperate exoplanets, LHS 1140 b could well be our best bet to one day indirectly confirm liquid water on the surface of an alien world beyond our solar system,” lead author Charles Cadieux said in a statement.
“This would be a major milestone in the search for potentially habitable exoplanets.”
The team, led by researchers from the Université de Montréal, examined data collected by Nasa’s James Webb Space Telescope.
It was added to earlier data from other telescopes including Spitzer and Hubble.
In their analysis, the scientists ruled out the possibility that LHS 1140 was a mini-Neptune with a hydrogen-rich atmosphere.
Rather, they found evidence that it is, in fact, a super-Earth – a rocky or watery planet with a radius roughly twice that of Earth’s.
Further analysis found reason to believe the exoplanet may have a nitrogen-rich atmosphere, similar to our home planet.
“This is the first time we have ever seen a hint of an atmosphere on a habitable zone rocky or ice-rich exoplanet,” said Ryan MacDonald, Nasa Sagan Fellow in the U-M Department of Astronomy.
“LHS 1140 b is one of the best small exoplanets in the habitable zone capable of supporting a thick atmosphere, and we might just have found evidence of air on this world.”
These findings suggest the planet has retained a substantial atmosphere and may accommodate liquid water.
And the scientists made another discovery that further supports the ocean theory.
LHS 1140 b is less dense than expected for an Earth-like planet, indicating a large fraction of its mass may be held in water.
This indicates LHS 1140 b is, in fact, a water world, likely resembling a snowball with an ocean pointing at the red dwarf like a bullseye.
Current models indicate that LHS 1140 b could bear an ocean roughly 4,000 kilometers in diameter, equivalent to half the surface area of the Atlantic Ocean.
The surface temperature could be a mild 20 degrees Celsius, or 68 degrees Fahrenheit.
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“Our initial reconnaissance of LHS 1140 b with JWST has revealed this to be perhaps the best habitable zone exoplanet currently known for atmospheric characterization,” MacDonald said.
“While we need more JWST observations to confirm the nitrogen-rich atmosphere, and to search for other gases, this is a very promising start.”
