An artist impression of Earth quasi-satellite Kamo`oalewa near the Earth-Moon system. Astronomers using the Large Binocular Telescope have shown that it may be a lost fragment of the Moon. Credit: Addy Graham/University of Arizona
A team of University of Arizona-led scientists thinks that the near-Earth asteroid Kamo`oalewa may really be a miniature moon.
A near-Earth asteroid called Kamo`oalewa could be a fragment of our moon, according to a brand-new paper released in Nature Communications Earth and Environment by a group of astronomers led by the University of Arizona.
Kamo`oalewa is a quasi-satellite– a subcategory of near-Earth asteroids that orbit the sun however stay fairly near to Earth. Since they are faint and hard to observe, little is understood about these things. Kamo`oalewa was discovered by the PanSTARRS telescope in Hawaii in 2016, and the name– found in a Hawaiian development chant– mentions an offspring that travels by itself. The asteroid is approximately the size of a Ferris wheel– between 150 and 190 feet in size– and gets as close as about 9 million miles from Earth.
Due to its orbit, Kamo`oalewa can just be observed from Earth for a few weeks every April. Its reasonably small size indicates that it can just be seen with one of the biggest telescopes in the world. Using the UArizona-managed Large Binocular Telescope on Mount Graham in southern Arizona, a team of astronomers led by planetary sciences college student Ben Sharkey found that Kamo`oalewas pattern of reflected light, called a spectrum, matches lunar rocks from NASAs Apollo missions, suggesting it stemmed from the moon.
The group cant yet be sure how it may have broken out. The factor, in part, is because there are no other recognized asteroids with lunar origins.
” I looked through every near-Earth asteroid spectrum we had access to, and nothing matched,” said Sharkey, the papers lead author.
The debate over Kamo`oalewas origins in between Sharkey and his adviser, UArizona associate professor Vishnu Reddy, led to another three years of hunting for a plausible description.
” We doubted ourselves to death,” said Reddy, a co-author who began the project in 2016. After missing out on the opportunity to observe it in April 2020 due to a COVID-19 shutdown of the telescope, the team found the final piece of the puzzle in 2021.
” This spring, we got much required follow-up observations and went, Wow it is genuine,” Sharkey said. “Its easier to explain with the moon than other concepts.”
Kamo`oalewas orbit is another clue to its lunar origins. Its orbit is comparable to the Earths, however with the tiniest tilt. Its orbit is also not typical of near-Earth asteroids, according to study co-author Renu Malhotra, a UArizona planetary sciences professor who led the orbit analysis part of the research study.
” It is extremely unlikely that a garden-variety near-Earth asteroid would spontaneously move into a quasi-satellite orbit like Kamo`oalewas,” she stated. “It will not remain in this specific orbit for very long, just about 300 years in the future, and we estimate that it arrived in this orbit about 500 years ago,” Malhotra said. Her lab is dealing with a paper to further investigate the asteroids origins.
Kamo`oalewa has to do with 4 million times fainter than the faintest star the human eye can see in a dark sky.
” These difficult observations were allowed by the enormous light gathering power, of the twin 8.4-meter telescopes of the Large Binocular Telescope,” stated research study co-author Al Conrad, a personnel scientist with the telescope.
Reference: “Lunar-like silicate material forms the Earth quasi-satellite (469219) 2016 HO3 Kamoʻoalewa” 11 November 2021, Communications Earth & & Environment.DOI: 10.1038/ s43247-021-00303-7.
The study also consisted of information from the Lowell Discovery Telescope in Flagstaff, Arizona. Other co-authors on the paper include Olga Kuhn, Christian Veillet, Barry Rothberg and David Thompson from the Large Binocular Telescope; Audrey Thirouin from Lowell Observatory and Juan Sanchez from the Planetary Science Institute in Tucson. The research study was funded by NASAs Near-Earth Object Observations Program.
An artist impression of Earth quasi-satellite Kamo`oalewa near the Earth-Moon system. Astronomers using the Large Binocular Telescope have actually shown that it might be a lost fragment of the Moon. Due to its orbit, Kamo`oalewa can just be observed from Earth for a few weeks every April. Its fairly little size implies that it can just be seen with one of the biggest telescopes on Earth. Kamo`oalewas orbit is another idea to its lunar origins.
