Overview
- Published in Science Advances, the study finds the Didymos–Dimorphos system slowed by about 11.7 micrometers per second, shortening its solar-orbit period by roughly 0.15 seconds.
- Researchers combined 22 stellar occultations recorded from October 2022 to March 2025 with nearly 6,000 ground-based astrometric measurements, plus DART navigation and radar data.
- Escaping debris roughly doubled the net momentum transfer (beta ≈ 2), indicating ejecta provided a push comparable to the spacecraft’s direct impact.
- The analysis constrains bulk densities to about 2.6 t/m³ for Didymos and 1.51 t/m³ for Dimorphos, supporting a porous rubble-pile structure for the smaller body; DART had earlier shortened Dimorphos’s local orbit by about 32–33 minutes.
- The system has never posed an Earth impact risk, the measured change is tiny but accumulative over time, and ESA’s Hera mission is expected to provide in-situ verification and refined properties when it arrives late in 2026.