Overview
- A study published in November 2026 modeled heat inside 1998 KY26 and found internal temperatures too high to preserve long‑lived water ice, reducing support for the 'dark comet' outgassing explanation for its extra push.
- Astronomers report a measurable non‑gravitational acceleration in 1998 KY26 that gravity alone does not explain; the object is very small at about 11 meters across, spins once every 5.35 minutes, and is relatively reflective.
- A separate team proposed in 2026 that some observations fit a model of the lost 1988 Soviet probe Phobos 1, but that artificial‑identity hypothesis fits some data without proving the object is a spacecraft.
- NASA officials say there is no evidence that 1998 KY26 is hazardous to Earth or that it is definitively artificial, and public statements aim to reassure that its small size makes surface impact unlikely.
- The most decisive test is JAXA’s Hayabusa2 rendezvous planned for July 2031, when in‑situ measurements of shape, mass, surface composition and direct spectroscopy should identify whether the body is natural or manufactured and will inform how subtle forces such as sunlight pressure and thermal emission move tiny space objects.