The Mystery of Asteroid Kamo'oalewa: Why It's Not from the Moon ⚡ экспресс
Asteroid Kamoʻoalewa is the target of China's Tianwen-2 sample-return mission. A hypothesis suggested it originated from the Moon as impact ejecta from the Giordano Bruno crater. A quantitative assessment was made of the contribution of main-belt objects versus the lunar scenario. Using models of the near-Earth asteroid population and calculating the fraction of quasi-satellite orbits, it was found that on average 1.23±0.13 Kamoʻoalewa-like objects arise from the main belt; the expected number of ejecta from Giordano Bruno is 0.042. Survey simulations showed that Pan-STARRS detects Earth's quasi-satellites with 95–70% efficiency for absolute magnitude H from 22 to 25, while the Vera C. Rubin Observatory will reach 92% for H≤25. The estimates align with the known population and support the main-belt origin of Kamoʻoalewa, which will be tested by the Tianwen-2 mission.
Kamo'oalewa is Earth's partner in a peculiar gravitational dance: it orbits the Sun almost in unison with us, edging closer and then pulling away. Its color — the palette of reflected light — matches the lunar surface. Hence the initial thought: it's a chunk of the Moon from the Giordano Bruno crater.
But calculations comparing brightness and orbits wiped out the romantic hypothesis. Such dancers from the main asteroid belt between Mars and Jupiter arrive at an average of 1.23 per epoch, while from that very crater — only 0.042. A gap of almost 30 times! The probability of Kamo'oalewa's lunar origin is laughable. More likely, it's simply a belt native that accidentally copied the lunar attire. In a year or two, the Tianwen-2 probe will collect soil samples — and the dance will end with a solution. Meanwhile, the Vera Rubin Observatory telescope watches its pirouettes.
🎯 Kamo'oalewa spans 40 to 100 meters — about as large as a few football fields — but through a telescope, it appears only as a faint point of magnitude 22. To spot it, you need equipment that captures light tens of times dimmer than what the eye can see.