A team of researchers led by the astronomer Charles Cadieux of the University of Montreal recently analyzed data collected by the James Webb telescope at NASA and discovered that the planet LHS 1140 b It could be a super-Earth rather than a mini-Neptune, as initially hypothesized. This planetlocated just 40 years light from us in the constellation of the Whale, represents one of the most Earth-like exoplanets ever discovered so far.
An ice giant with an ocean beneath its surface
When LHS 1140 b was discovered in late 2023, it was thought to be a mini-Neptune. However, new data suggest that the planet is a super-Earth, a terrestrial world more massive than ours. Thanks to its proximity to a red dwarf star coldLHS 1140 b could to be a gigantic globe of ice with an ocean substellar which makes it look like a “cosmic eye”. This makes it one of the best candidates for the presence of liquid water on the surface, increasing the chances of habitability.
LHS 1140 b: atmosphere and climatic conditions
The team of Caddieux he found “fascinating evidence of a nitrogen-dominated atmosphere” in a habitable zone of this exoplanet. The data were collected using the NIRISS (Near-Infrared Imager and Slitless Spectrograph) to edge of the telescope Webbspecialized in the detection of exoplanets through spectroscopy of transitThis technique allows you to identify the atoms and molecules present in the atmosphere of the planet.
Climate models and alternative hypotheses
To verify the initial hypothesis of a mini–Neptuneresearchers have created a model three-dimensional global climate model (GCM) that simulates the various factors that make up a planet’s climate system. However, spectroscopic data do not they corresponded to the models of a mini–Neptunebut they lined up Better with those of a super–Earth. This type of planet would typically have a thick atmosphere of nitrogen or CO2, enveloping a rocky surface with the presence of water, either solid or liquid.
Studies also suggest the presence of a second atmospheremade up of heavier elements such as water vapor, carbon dioxide and methane, released by the crust of the planet.
A planet with hidden oceans?
The data of the Webb/NIRISS indicate that LHS 1140 b has a lower density than expected for a rocky world, consistent with a planet of waterwhose 10-20% of the mass could be composed of water. This discovery opens up the possibility that LHS 1140 b is a planet hyceanan ocean world with an atmosphere dominated from hydrogen.
Despite the discoveries promisingfurther observations are needed to confirm the nature of LHS 1140 b. Cadieux and his team intend to compare the data of the NIRISS with those collected by other instruments of the telescope Webb And drive further observations to exclude the interference of stellar radiation.
Could this really be a frozen Earth? There suspense It will last a few more years.
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