Observed facts
- Its trajectory was unbound to the Sun, indicating that it came from outside our Solar System.
- Brightness variations imply an extreme, elongated or flattened shape, although its exact shape was not directly resolved.
- The object showed a small deviation from a purely gravitational path without an obvious visible coma or tail.
Leading scientific explanations
- Very weak outgassing from an unusual volatile could provide the acceleration without a bright dust coma.
- Radiation pressure or a fragment of an icy body have been explored in published work.
- The available observations are sparse because the object was discovered after its closest solar approach.
What remains uncertain
Its composition, origin system, and the physical cause of the acceleration remain uncertain. Later interstellar visitors will provide the useful comparison.