Fastest spinning asteroid spotted by Rubin Observatory rotates in under two minutes

Astronomers using the Vera C. Rubin Observatory's LSST camera identified an asteroid about 710 meters across that rotates once every 1.88 minutes; the study reports its orbit does not intersect Earth's and no impact warnings were issued.

Researchers using the Vera C. Rubin Observatory's LSST camera have identified a group of very fast-spinning asteroids during the observatory's early observations. The team examined 76 asteroids and found 19 super- and ultra-fast rotators. One object, 2025 MN45, measures about 710 meters across — roughly eight football fields — and completes a rotation in about 1.88 minutes. The results were published in The Astrophysical Journal Letters. Key details: - The discovery was made with the LSST camera on the Vera C. Rubin Observatory during early commissioning, with 19 ultra- and super-fast rotators reported among 76 asteroids surveyed. - 2025 MN45 is reported to be roughly 710 meters in diameter and to rotate once every ≃1.88 minutes, making it the fastest-spinning known asteroid of its size in this sample. - Other highlighted objects include 2025 MJ71, 2025 MK41, 2025 MV71, and 2025 MG56, with rotation periods of ≃1.92, ≃3.78, ≃13, and ≃16 minutes respectively. - The authors report that MN45 would need cohesive strength similar to solid rock to remain intact at its spin rate, which differs from the typical "rubble pile" structure often assumed for many asteroids, as noted by Sarah Greenstreet. - The study states the asteroid's trajectory does not coincide with Earth's and it did not attach any impact warnings. - The findings are described in the paper "Lightcurves, rotation periods, and colors for Vera C. Rubin Observatory's first asteroid discoveries" in The Astrophysical Journal Letters (DOI: 10.3847/2041-8213/ae2a30). Summary: The discovery adds new observational evidence about asteroid rotation and internal strength, especially for main-belt objects that have been harder to study at this scale. Rubin's LSST survey, slated to run for ten years, is expected to produce more detections and data on similar fast rotators as the survey progresses.