A team of astronomers has taken our search for planets containing liquid water outside the Solar System. The exoplanet LHS 1140 b it appears to be a world completely covered in ice and may harbor an atmosphere and even a liquid ocean.
First discovered in 2017, the LHS 1140 b it lies in its star’s habitable zone and until then appeared to be an essentially gaseous planet, but data from the James Webb Space Telescope collected in December 2023, compared with previous data from other space telescopes such as Spitzer, Hubble and TESS, changed this perspective.
Scientists, led by the University of Montreal, believe this exoplanet could be a completely ice-covered world, with the possibility of even containing a liquid ocean beneath a cloudy atmosphere.
These signs make the LHS 1140 b one of the most promising planets as a potential habitable world. The study has been approved for publication in The Astrophysical Journal Letters.
Habitable zone
O LHS 1140 b orbits a low-mass red dwarf star, approximately one-fifth the size of the Sun, and is located about 48 light-years from Earth in the constellation Cetus.
A video released by the European Southern Observatory (ESO) in 2017, after the discovery of the exoplanet, shows an artistic simulation of an imaginary journey from Earth to the Earth. LHS 1140 b. Check out:
Its discovery had already caught the attention of astronomers because it is one of the exoplanets (planets outside our Solar System) closest to Earth that lies within the habitable zone of its star. In other words, it is at a distance that allows the temperature for water to exist in liquid form.
O LHS 1140 b it is 1.7 times the size of Earth and 5.6 times its mass. The new data suggests that the exoplanet can be considered a super-Earth (a rocky planet with greater mass than Earth), rather than a mini-Neptune (a gaseous planet with a thick, hydrogen-rich atmosphere slightly smaller than Earth). Neptune), as it initially appeared.
Possibility of water
Although scientists have not yet been able to confirm these suspicions, the presence of a nitrogen-rich atmosphere suggests that the LHS 1140 b would have the necessary conditions for the existence of liquid water.
According to estimated models, if this were really the case, the planet would resemble an eyeball — a snowball with an ocean on one side in the shape of an “iris”. The temperature in this ocean could reach a comfortable 20°C.
To be able to prove their hypotheses, however, astronomers still have several years to go.
“The current suggestion of a nitrogen-rich atmosphere begs confirmation with more data. We need at least another year of observations to confirm that the LHS 1140 b it has one atmosphere, and probably two or three more to detect carbon dioxide,” explained René Doyon, a professor at the University of Montreal who supervised the study.
“Detecting an Earth-like atmosphere on a temperate planet is pushing Webb’s capabilities to the limit. It’s feasible, we just need a lot of observation time,” he added.
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