Astronomers find surprising ice world in the habitable zone with JWST data
A surprising ice-world exoplanet within the habitable zone has been discovered by astronomers using data from the James Webb Space Telescope (JWST). The planet, called LHS 1140 b, is a super-Earth, potentially consisting of ice or water. It is situated about 48 light-years away in the constellation Cetus, and is considered one of the most promising candidates for supporting life due to its location within the habitable zone and its potential for harboring an atmosphere and liquid water oceans. The findings, led by Université de Montréal, were recently accepted for publication in The Astrophysical Journal Letters.
The analysis of LHS 1140 b's atmosphere was a significant achievement due to its rocky or ice-rich composition, which makes detecting atmospheres more challenging compared to gas giants. Ryan MacDonald, a NASA Sagan Fellow in the U-M Department of Astronomy, who played a key role in the analysis, expressed his excitement about detecting an atmosphere on a potentially habitable exoplanet for the first time.
LHS 1140 b revolves around a low-mass red dwarf star, smaller than our Sun, and is one of the closest exoplanets discovered within the habitable zone of its star system. The habitable zone refers to a range where temperatures permit liquid water to exist, a crucial ingredient for life as we know it. Determining whether the exoplanet was a mini-Neptune or a super-Earth was a crucial question for scientists. The recent findings strongly suggest that LHS 1140 b is a super-Earth, adding to the excitement surrounding its potential habitability.
With the inclusion of JWST data, observations strongly indicate that LHS 1140 b is less dense than expected for a rocky planet and may contain a significant amount of water, up to 20% of its mass. The planet might resemble a snowball or ice planet, with a potential sub-stellar point liquid ocean due to its synchronous rotation. Although the presence of a nitrogen-rich atmosphere has yet to be confirmed by additional JWST observations, Ryan MacDonald's atmospheric analysis suggests the planet could support an atmosphere similar to Earth's nitrogen-rich composition. This discovery further supports the theory of LHS 1140 b being a captivating water world.
The potential presence of an atmosphere and the favorable conditions for liquid water make LHS 1140 b an exceptional candidate for future habitability studies. With its positioning in the habitable zone and the likelihood of a stable climate, researchers have an exciting opportunity to explore a world that could potentially support life. The relatively calm and less active nature of the star LHS 1140 also contributes to the feasibility of studying LHS 1140 b's atmosphere without interference from stellar signals caused by starspots.
As we eagerly anticipate more JWST observations to confirm the nitrogen-rich atmosphere and to search for other gases, these preliminary findings serve as a promising start in understanding the atmospheric makeup and habitability of LHS 1140 b. Future studies focused on this intriguing exoplanet will shed more light on the potential for life beyond our solar system.
