Scientists analyze the first images Vera K. Rubin Observatory discovered the fastest rotating asteroid in its size class.
The record-breaking space rock, called 2025 MN45, is larger than most skyscrapers on Earth and is about 2,300 feet (710 meters) wide. The massive rock orbits in about 113 seconds, making it the fastest-spinning asteroid known at more than 1,640 feet (500 meters) in diameter.
The study is the first peer-reviewed paper from Rubin Observatory's LSST camera—the world's largest digital camera—which will repeatedly scan the night sky of the Southern Hemisphere over 10 years to create an unprecedented time-lapse movie of the universe.
Rocks that roll
Asteroids are essentially large space rocks, and many of them are remnants of how our solar system appeared at the beginning of its 4.5 billion-year history, before the evolution of planets and satellites. Therefore, by studying asteroids, scientists will be able to figure out how our solar system has changed over millennia.
Scientists discovered 2025 MN45 using pre-release data from the Rubin Observatory, which has already discovered thousands of previously unknown asteroids around the solar system in just seven nights of observation. (The 10-year LSST study has not yet officially begun, but is expected to begin in the next few months.)
The asteroid's surprisingly fast rotation has the team excited because it provides clues to the composition of the ancient rock.
“Obviously, this asteroid must be made of a material that has very high strength in order to keep it intact.” Sarah GreenstreetThis was reported by an assistant astronomer at the National Science Foundation's National Research Laboratory for Optical and Infrared Astronomy. statement. “This would require adhesive strength similar to that of solid rock.”
“It's a little surprising,” added Greenstreet, who also heads Rubin's Near-Earth Object Working Group and interstellar objects“because most asteroids are considered to be what we call a 'debris pile,' meaning that they are made up of many, many small pieces of rock and debris that were fused together by gravity during the formation of the solar system or subsequent impacts.”
Thousands more to come
In general, rapidly spinning asteroids could have reached this state after colliding with another space rock, the research team said. It is also possible that 2025 MN45 is the remnant of a much larger asteroid destroyed in a cosmic crash.
Most of the solar system's asteroids are found in the main asteroid belt between Mars and Jupiter. But most of the fast-rotating asteroids that astronomers have observed are much closer to Earth simply because they are easier to see, the study authors noted. 2025 MN45 is a main belt object where most asteroids (since they are loose piles of debris) require at least 2.2 hours to rotate to avoid fragmentation. Anything that spins faster “must be structurally sound,” they wrote.
However, 2025 MN45 is not the only rapidly rotating object in the main asteroid belt. In addition to 2025 MN45, Rubin's first data set includes 16 “ultra-fast” rotators, each with a rotation period ranging from 13 minutes to 2.2 hours, as well as two “ultra-fast” rotators with a rotation of less than two minutes each. All of these asteroids are also more than 100 yards (90 m) long, and all but one of the newly discovered asteroids are found in the main belt.
Rubin's commissioning data, which was published last June, was analyzed in more depth in a new paper that was also discussed Wednesday at a press conference at the 247th meeting of the American Astronomical Society in Phoenix.
According to the statement, the huge body of observations includes approximately 1,900 never-before-observed asteroids. There will be many more when Rubin officially begins its 10-year survey of the skies in the coming months.
