- NASA's James Webb Telescope observed the atmosphere and surface of exoplanet LHS 3844 b
- LHS 3844 b is a rocky super-Earth 30% larger than Earth orbiting a red dwarf star every 11 hours
- The planet is tidally locked with a scorching dayside averaging 725°C and no atmosphere
NASA's James Webb Space Telescope has observed the atmosphere of a distant exoplanet and directly at its surface for the first time, revealing a scorching "super-Earth" that looks more like Mercury or the Moon than Earth. The exoplanet in question is LHS 3844 b, which is a rocky world about 30% larger than Earth. It circles a cool red dwarf star in just under 11 hours. It orbits just three stellar diameters above the star's surface, which is about 0.006 AU, or one-fortieth the distance from Mercury to the Sun. It is just 48.5 light-years away, but any resemblance to our home ends there.
That extreme proximity has tidally locked the planet, meaning the same hemisphere always faces the star. It means a planet with a permanent dayside, with an average temperature of 725 degrees C (1,340 degrees F). Night never falls on that side.
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"This is a brutal place," said Laura Kreidberg, Director at the Max Planck Institute for Astronomy and principal investigator of the study. "Thanks to the amazing sensitivity of JWST, we can detect light coming directly from the surface of this distant rocky planet. We see a dark, hot, barren rock, devoid of any atmosphere."
Using JWST's Mid-Infrared Instrument (MIRI), researchers measured heat radiating directly from the planet's scorched dayside. The findings of the observations were published on May 4, 2026, in Nature Astronomy.
The infrared spectrum best matches a dark, low-silica surface made of basalt or olivine-rich rock - the same stuff that covers Mercury and the lunar maria.
That rules out an Earth-like, silica-rich crust formed by plate tectonics and liquid water. "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 team wrote.
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Without an atmosphere to shield it, LHS 3844 b is bombarded by stellar radiation and micrometeorites. That constant exposure breaks rock into fine regolith and darkens the surface through "space weathering".
"No volcanic gases such as CO2 or SO2 were detected," researchers noted. If volcanism exists, it isn't producing a thick atmosphere.
Astronomers couldn't photograph LHS 3844 b directly. Instead, they watched how the combined light of the star and planet changed as the planet orbited.
When the hot dayside faces Earth, it adds a tiny bit of infrared light to the star's glow. When the cold nightside faces us, that extra light vanishes. The team built a thermal emission spectrum by comparing brightness at different wavelengths.
