"LHS 1140 is a cool low-mass star approximately 39 light-years away in the constellation of Cetus.
LHS 1140 is known to host three exoplanets: LHS 1140b, LHS 1140c and LHS 1140d.Earlier this year, astronomers reported new mass and radius estimates for LHS 1140b with exceptional accuracy, comparable to those of the well-known TRAPPIST-1 planets: 1.7 times the size of Earth and 5.6 times its mass.
An analysis of the new Webb observations strongly excluded the mini-Neptune scenario, with tantalizing evidence suggesting exoplanet LHS 1140b is a super-Earth that may even have a nitrogen-rich atmosphere.
Estimates based on all accumulated data reveal that LHS 1140b is less dense than expected for a rocky planet with an Earth-like composition, suggesting that 10 to 20% of its mass may be composed of water.
If this result is confirmed, LHS 1140b would be the first temperate planet to show evidence of a secondary atmosphere. This discovery points to LHS 1140b being a compelling water world, likely resembling a snowball or ice planet with a potential liquid ocean at the sub-stellar point, the area of the planet’s surface that would always be facing the system’s host star due to the planet’s expected synchronous rotation."
SciNews