Scientists using the James Webb Space Telescope have identified LHS 1140 b, a nearby exoplanet located just 49 light-years away in the constellation Cetus, as a promising candidate for finding water and potentially an Earth-like atmosphere. This exoplanet, which is 1.7 times the size of Earth, has been under scrutiny since its discovery in 2017 by the MEarth Project. Recent data collected by JWST in December 2023 has revealed the possibility of an atmosphere and even a liquid water ocean on LHS 1140 b.
Researchers believe that LHS 1140 b could be a “snowball” or ice planet, with an estimated 10 to 20% of its mass being water. The planet is tidally locked to its star, meaning it always shows the same side to its star, which could potentially mean that any liquid ocean exists on its permanently dark side. If this is the case, scientists estimate that the ocean could be 2,500 miles in diameter, with a surface temperature of 68 degrees Fahrenheit.
Despite being a “super-Earth” that is seven times the mass of Earth, LHS 1140 b orbits a red dwarf star, one of the most common types of stars in the Milky Way. This red dwarf star is much smaller and dimmer than our sun, allowing LHS 1140 b to be in the habitable zone where water can exist as a liquid. This is significant as water is believed to be essential for life. The star LHS 1140 is considered calmer and less active compared to other habitable zone exoplanets, making it easier to study LHS 1140 b’s atmosphere.
Researchers hope to find a nitrogen-rich atmosphere on LHS 1140 b, similar to Earth’s atmosphere. While initial observations suggest the presence of an atmosphere on this exoplanet, more JWST observations will be needed to confirm the signature of nitrogen gas and search for other gases. Due to the limitations of the JWST, astronomers estimate that several years of observations will be required to detect carbon dioxide and confirm the presence of liquid water on the planet’s surface. Progress in studying LHS 1140 b’s atmosphere and potential for supporting life will be gradual.
The discovery of LHS 1140 b as a potential habitable exoplanet marks a significant milestone in the search for planets beyond our solar system that could support life. With advances in technology such as the James Webb Space Telescope, scientists are able to study distant exoplanets in greater detail and uncover clues about their atmospheres and potential for harboring water. The findings about LHS 1140 b have sparked excitement in the scientific community and raise hopes for discovering other habitable worlds in the future.
