Discovered in 2017 by the MEarth Project,[1] LHS 1140 b is about 5.6 times the mass of Earth and about 70% larger in radius, putting it within the super-Earth category of planets.

[2] The planet is 49 light-years away and transits its star, making it an excellent candidate for atmospheric studies with ground-based and/or space telescopes.

In addition, LHS 1140 is a very inactive star, with no major flare events found by the discovery team of its planet.

[1] LHS 1140 b has been detected using both the radial velocity method (which measures the mass of a companion object) and transit photometry (which determines radius).

While this is quite close, the star LHS 1140 is so dim that the planet only gets 0.43 times the incident flux of Earth at this distance.

Like many potentially habitable planets around red dwarfs, the orbit of LHS 1140 b is quite circular: the eccentricity is measured to be lower than 0.29 to a 90% confidence.

[1] Later studies in 2018 and 2020 revised the planet's radius upwards, giving it a density of 7.82+0.98−0.88 g/cm3, still consistent with a rocky composition, and a lower core mass fraction of 49±7%.

[5] A potential detection of water vapor in the atmosphere of LHS 1140 b was made in late 2020 with the Hubble Space Telescope, albeit at a low signal-to-noise ratio.

[5] In July 2024, tentative hints of atmospheric nitrogen were detected by JWST, suggesting that the surface of planet might be mostly ice and partially covered in liquid water, which resembles an eyeball.