Emily Chan
Several years ago, the James Webb Space Telescope (JWST) spied a planet in the distance. It is located about 50 light-years away from Earth and is a contender for a potentially habitable world. It could be an “eyeball” planet with an ocean in the middle, resembling an iris, and surrounded by solid ice.
The exoplanet LHS-1140b was discovered in 2017. It orbits a low-mass red dwarf star that is approximately one-fifth the size of the sun. At first, astronomers believed it was like a smaller version of Neptune, with water, ammonia, and methane.
But, after analyzing data that was collected from the telescope in 2023, they reached a different conclusion. They found that the planet was icier and wetter than previously thought. It might contain an atmosphere and possibly even an ocean of liquid water, showing much promise for supporting life.
“Of all currently known temperate exoplanets, LHS-1140b could well be our best bet to one day indirectly confirm liquid water on the surface of an alien world beyond our Solar System,” said Charles Cadieux, an astrophysicist at the University of Montreal. “This would be a major milestone in the search for potentially habitable exoplanets.”
LHS-1140b rotates at the same rate as it closely orbits its host star. One year for the planet equates to about 25 Earth days. Its close orbit of its star places it in what is called a “Goldilocks Zone.” This area contains exoplanets with temperatures that could allow liquid water to exist on them.
To study the exoplanet, researchers used the telescope’s Near-Infrared Imager and Slitless Spectrograph. They assessed the wavelengths of light coming from its star toward Earth and spotted signs of nitrogen, a crucial element in Earth’s atmosphere.
Additional calculations revealed that the planet was less dense than expected, so it could not be made of rock. Estimates suggest that 10 to 20 percent of the planet’s mass may be composed of water.
Together, these findings seem to invalidate the idea that the planet was like a miniature Neptune. Instead, it is more likely that the planet is covered in ice.
The researchers acknowledged that most of the planet might be frozen, but the “iris” could reach 68 degrees Fahrenheit. That is warm enough for marine life to survive in the frozen world.
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