Explain ’Oumuamua’s non-gravitational acceleration without detected outgassing

Determine the physical mechanism responsible for the non-gravitational acceleration of the interstellar object 1I/'Oumuamua that is consistent with the absence of infrared detections of outgassing or dust, reconciling all available observational constraints on composition and activity.

Background

The paper highlights a key observational paradox from the first confirmed interstellar object, 1I/'Oumuamua: precise astrometric measurements indicate non-gravitational acceleration, yet infrared observations failed to detect outgassing or dust typically implicated in such accelerations. This contradiction undermines standard cometary-driven explanations and leaves the object’s dynamics unresolved.

Resolving this discrepancy is central to interpreting interstellar object phenomenology, constraining plausible physical models (e.g., volatile-driven activity, radiation pressure effects, or alternative mechanisms), and informing the design of rapid-response observation strategies and instrumentation for future ISO encounters.