JWST Detects Volcano-Driven Atmosphere on Rocky Exoplanet LHS 3844 b
Image Credit: NASA, ESA, CSA, STScI
Astronomers have crossed a monumental threshold in the search for characterized rocky worlds. Using the Mid-Infrared Instrument (MIRI) aboard the James Webb Space Telescope, an international team has detected definitive signs of a thin, secondary atmosphere on the Earth-sized exoplanet LHS 3844 b—fueled entirely by extreme volcanic activity.
Probing a Lava World's Horizon
LHS 3844 b orbits its host M-dwarf star so closely that its dayside is a permanent ocean of molten rock. Initial studies suggested the planet was a bare, airless rock, but JWST’s ultra-precise phase curve observations have painted a drastically different picture.
As the planet rotated, the telescope captured distinct chemical fingerprints that could only exist if sustained by an active interior:
- Sulfur Dioxide Peaks: The infrared spectrum revealed a significant abundance of $SO_2$, a classic byproduct of volcanic eruptions.
- Silicate Smog: Thermal emission data indicates a persistent haze of microscopic rock particles suspended just above the molten surface.
Geological Implications
This discovery confirms that rocky planets orbiting volatile red dwarf stars can retain or rebuild an atmosphere through volcanic activity. This provides a crucial piece of the puzzle for understanding how early Earth, Venus, and Mars managed to sustain their atmospheres during their chaotic formative years.