Researchers from the University of Washington, led by Dmitrii Vavilov, identified asteroid 491384 using data from the Vera C. Rubin Observatory. The asteroid has a diameter of approximately 2.53 kilometers and a rotation period of 4.18 minutes, making it the largest known asteroid with a diameter exceeding 2 kilometers to exhibit such high-speed rotation.
The team developed automated software to estimate rotation periods by analyzing asteroid brightness variations. This method addresses challenges in data sampling and potential measurement errors. The software was tested on 9,417 asteroids from the observatory's second data preview, identifying 66 candidates that exceed the traditional rotation barrier, including asteroid 566130 with a 5-minute rotation period.
The findings, published on arXiv on October 6, suggest that these large, fast-rotating asteroids must possess significant internal cohesive strength to prevent disintegration from centrifugal forces. This challenges the common model of asteroids as loose rubble piles. The study remains a preprint and awaits peer review and further observational confirmation.
The research team intends to refine the software for larger-scale astronomical surveys. By automatically identifying anomalous brightness measurements, the tool aims to improve the reliability of rotation period estimates and detect potential errors in telescope exposure data.
