Astronomers Use Webb Telescope to Study Exoplanet Surface Beyond Atmosphere

Astronomers have, for the first time, moved beyond studying the exoplanet's atmosphere and analysing its surface directly. With the help of the James Webb Space Telescope (JWST), researchers analysed a terrestrial exoplanet named LHS 3844 b, which is nearly 30% larger than Earth and located about 48.5 light-years from Earth. These details have been released in the peer-reviewed journal Nature Astronomy on May 4, 2026.

A Planet That Resembles Mercury More Than Earth

According to NASA, the LHS 3844 b orbit completes around its star in the brief 11 hours, swinging a paltry three stellar diameters about the surface of its star. It is tidally locked, i.e., the same hemisphere always faces the star, causing dayside temperatures to reach around 725 C (1,340 F). The team used the Mid-Infrared Instrument (MIRI) of the JWST to measure the heat radiating directly off of this scalded surface. The spectrum is only best matched by a dark, low-silica surface of basalt or olivine-rich material, eliminating the possibility of an Earth-like silica-rich crust - the one formed through plate tectonics and liquid water. The planet is closer to becoming a bigger and hotter planet like Mercury or the Moon.

Space Weathering and What Comes Next

Due to the lack of an atmosphere, the exoplanet is subject to constant radiation and micrometeorite bombardment, which causes rock to disintegrate into tiny particles referred to as regolith and change its chemical makeup through space weathering. Notably, no volcanic gases such as CO₂ or SO₂ were detected. The team has obtained additional JWST observations aimed at discerning surface conditions by exploiting small differences in the data. Scientists believe this technique will eventually unlock the geological histories of many other rocky worlds beyond our solar system.