A team of Chinese astronomers from Yunnan Observatory, in collaboration with international partners, has made a significant breakthrough in the study of super-fast near-Earth asteroids. They have confirmed the discovery of the fastest-known near-Earth asteroid, which completes a full rotation on its axis in a mere 1.63 seconds. The findings of this research have been published in the esteemed international astronomical journal “The Astronomical Journal”.
What Are Near-Earth Asteroids?
Near-Earth asteroids (NEAs) are celestial bodies whose orbits bring them in close proximity to Earth. Specifically, this category includes asteroids with a perihelion distance of less than 1.3 astronomical units (AU). Particular attention is paid to potentially hazardous asteroids (PHAs), which have a diameter exceeding 140 meters and a minimum orbit intersection distance with Earth of less than 0.05 AU. The growing concern regarding the threat posed by potential impacts from such objects stems from their immense destructive power, making their monitoring, early warning, and defense critically important for the safety of all humanity.
Successful Impact Prediction
On December 4, 2024, during the night of December 3rd to 4th Beijing time, the near-Earth asteroid 2024 XA1 entered Earth’s atmosphere over Eastern Siberia. The entire process, from its detection to its impact, lasted approximately 10 hours. This marked the 11th successful prediction of a near-Earth asteroid’s collision with Earth in recorded history.
Observation and Analysis
To gather precise data on the brightness of 2024 XA1, the Yunnan Observatory team utilized the 2.4-meter telescope located in Lijiang. Employing the “wait and watch” method (守株待兔), scientists were able to capture images of the asteroid in the final hour before its atmospheric entry, providing an exceptionally valuable observation window.
Extremely Rapid Rotation
Analysis results revealed that the rotation period of the near-Earth asteroid 2024 XA1 is a mere 1.63 seconds. This is significantly faster than the previous record holder, asteroid 2024 BX1, which rotated in 2.58 seconds. Consequently, 2024 XA1 has set a new record as the fastest-known near-Earth asteroid.
Structure and Origin
At such extreme rotational speeds, the centrifugal force on the asteroid’s surface considerably exceeds its gravitational pull. This indicates that 2024 XA1 is not merely a loosely bound pile of rubble held together by gravity. Instead, its integrity is maintained solely by the mechanical strength of its rocky materials, suggesting it belongs to the class of solid monolithic bodies where cohesive forces dominate. Scientists hypothesize that these unique characteristics might be the result of a collision with another large cosmic object, which led to its fragmentation.
Significance of the Research
This research holds considerable importance, not only for confirming 2024 XA1’s status as the fastest near-Earth asteroid. It also opens new avenues for studying the internal structure of small, rapidly rotating, and fast-moving near-Earth asteroids. Furthermore, this work significantly enhances scientists’ ability to gather information on the physical properties of short-warning asteroids.
Research Paper Link: https://doi.org/10.3847/1538-3881/aeaa5d
