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Twelve Transits Ruled Out Moons One-Tenth Earth's Radius
JWST found no moon around LP 890-9c, but excluded objects comparable in size to several Solar System moons across the planet's Hill region.
Summary
JWST found no moon around LP 890-9c, but excluded objects comparable in size to several Solar System moons across the planet's Hill region.
The search combined twelve JWST transits of the rocky temperate-zone exoplanet LP 890-9c. It found no exomoon and reports a 95-percent exclusion of moons at 0.1 Earth radii across the full Hill region, a scale that includes analogs of Europa, Rhea and Umbriel. The authors caution that LP 890-9c orbits at 0.04 astronomical units, where tides already make long-term survival of larger moons unlikely. The main instrument result is sensitivity: pairing a noisy transit with one clean epoch restored limits comparable with other two-epoch combinations.
Why it matters
JWST found no moon around LP 890-9c, but excluded objects comparable in size to several Solar System moons across the planet's Hill region.
Limits and context
No additional limitation was separately recorded.
Key claims
JWST found no moon around LP 890-9c, but excluded objects comparable in size to several Solar System moons across the planet's Hill region.
Evidence: source-2026-09-08-007
Sources
- arXiv preprint 2609.05301arXiv · primary research
Corrections
No corrections have been recorded for this story.