James Webb Detects Clay on 2 Neptune Moons, Hinting Triton Shattered Larger Worlds
Updated
Updated · spacedaily.com · Aug 21
James Webb Detects Clay on 2 Neptune Moons, Hinting Triton Shattered Larger Worlds
1 articles · Updated · spacedaily.com · Aug 21
Summary
Spectra from Webb’s NIRSpec found a 2.72-micrometre signature of magnesium-rich phyllosilicate clay on Neptune’s inner moons Larissa and Galatea, with similar hydrated material also seen in nearby rings.
Those minerals typically form when liquid water alters rock for roughly 1 million to 10 million years at below about 300 to 400 kelvin—conditions the 200-kilometre moons, now near 50 kelvin, could not have sustained.
The study argues the clay is older than the present moons and likely came from the interiors of much larger, differentiated satellites that were shattered, with only about 1% of the original material surviving in today’s inner system.
Triton is the leading culprit: its capture into a retrograde orbit could have destabilized Neptune’s native moons, driving collisions, ejections and reaccretion, though a disrupted Kuiper Belt interloper remains an alternative.
Proteus lacks a comparably strong clay band, and with Voyager 2 still Neptune’s only close visit since 1989, researchers say more spectra, lab work and dynamical modeling are needed to reconstruct the system’s history.