A near-Earth asteroid could be part of our moon

A near-Earth asteroid called Kamo’oalewa It could be part of our moonAccording to a new article published in the magazine Nature Communications Earth and Environment By a team of astronomers led by the University of Arizona in the United States.

Kamo’oalewa is a semi-satellite, a subclass of near-Earth asteroids that orbit the Sun but remain relatively close to Earth. Not much is known about these objects because they are faint and difficult to monitor.

Discovered by the PanSTARRS telescope in Hawaii in 2016, the name — found in the Hawaiian creation hymn — refers to a shrub traveling alone. The asteroid is about the size of a Ferris wheel – between 45 and 57 meters in diameter – and lies within 1.4 million kilometers of Earth.

Due to its orbit, Kamo’oalewa can only be seen from Earth for a few weeks each April. Its relatively small size means it can only be seen with one of the largest telescopes on Earth.

Why do you think the asteroid originated on the moon?

Using the Mount Graham Large Binocular Telescope operated by the UA in southern Arizona, a team of astronomers led by planetary science student Ben Sharkey discovered that Kamo’oalewa’s pattern of reflected light, called a spectrogram, matches lunar rocks from NASA’s Apollo missions, indicating its origin on the Moon. .

The team is still not sure how this happened. The reason, in part, is that no other asteroids of lunar origin are known.

“I looked at all the spectra of near-Earth asteroids that we had access to, and nothing matched them,” explains Sharkey, the paper’s lead author.

The controversy over the origin of Kamo’oalewa between Sharkey and his advisor, UArizona Associate Professor Vishnu Reddy, led to another three years of searching for a plausible explanation. “We doubt the nausea,” admits Reddy, the co-author who started the project in 2016. After missing the chance to see it in April 2020 due to a COVID-19 telescope outage, the team found the final piece of the puzzle in 2021.

This spring, we got much-needed follow-up notes and said, ‘Wow, it’s real,’ says Sharkey. It’s easier to explain with the moon than with the other ideas. “

Kamo’oalewa’s orbit is another clue to the moon’s origin. Its orbit is similar to that of the Earth, but with a slight tilt. Its orbit is also not typical for near-Earth asteroids, according to Renu Malhotra, study co-author and UArizona professor of planetary sciences who led the orbital analysis division of the study.

Malhotra continues: “It is highly unlikely that a common asteroid would spontaneously move into close orbit to satellites like Kamo’oalewa.” It won’t stay in this particular orbit for long, only about 300 years into the future. We estimate that it reached this orbit about 500 years ago.”

His laboratory is working on an article to further investigate the origin of the asteroid.

Kamo’oalewa is about 4 million times fainter than the darkest star the human eye can see in a darkened sky.

“These challenging observations are made possible by the enormous light-gathering capabilities of the twin 8.4-meter telescopes in the Big Eyed Telescope,” says Al Conrad, co-author of the study and telescope scientist.

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