LHS 3844 b
Rocky super-Earth exoplanet orbiting the M dwarf star LHS 3844, 48.5 light-years from Earth. Discovered by TESS in 2018. Key parameters: ~1.3 R⊕ (30% larger than Earth), dayside temperature ~1000 K, ~11-hour orbital period, tidally locked.
JWST Atmospheric Null Result (2026)
A May 2026 Nature Astronomy study (Zieba et al., PI Laura Kreidberg at MPIA) used JWST MIRI thermal emission spectroscopy (5–12 µm) to characterize LHS 3844 b’s surface and atmosphere. Findings:
- No detectable atmosphere: strict upper limits of 100 mbar CO₂ and 10 µbar SO₂
- Surface spectrum matches low-silica, space-weathered basalt or olivine-rich rock — consistent with Mercury or Earth’s Moon
- Absence of a fresh silicate crust implies plate tectonics do not apply to this world
- Reinforces the pattern that short-period rocky planets around M dwarfs lose their atmospheres rapidly
The result rules out LHS 3844 b as a biosignature-hunting target and constrains models of atmospheric retention on M-dwarf rocky planets.
Interior-modeling counterpoint (July 2026)
A July 2026 laboratory mantle-convection study (src-tidally-locked-exoplanet-habitability-2026-07, Noto et al., Nature Communications) uses LHS 3844 b as its illustrative example of a tidally locked exoplanet, finding that steady dayside-to-nightside mantle convection could sustain localized mid-latitude geothermal habitability despite extreme surface temperature contrast. This is an interior-geophysics finding, not an atmospheric one — it does not contradict the JWST atmospheric null result above, since the two studies address different physical layers of the planet (interior heat transport vs. surface/atmosphere composition).
Sources
- src-jwst-lhs-3844b-bare-rock-2026
- src-tidally-locked-exoplanet-habitability-2026-07 — Jul 2026: laboratory mantle-convection model using LHS 3844 b as illustrative example