ARC-led Collaboration Confirms Discovery of New Minimoons in Next Decade
A global collaboration led by a research fellow from the School of Mathematics and Physics which detected only the second minimoon ever recorded earlier this year has confirmed that many more will be found in the next decade.
The findings of the study, which described the minimoon, a free-floating silicate boulder named 2020 CD3, have been published in the Astronomical Journal (Monday November 23).
Minimoons are small asteroids temporarily captured in Earth鈥檚 orbit before they are flung back out into space.
, a postdoctoral research fellow from the in the School of Mathematics and Physics who led the multi-telescope observational campaign, described the sighting of the minimoon on 15 February as 鈥渁 rare treat for astronomers鈥.
2020 CD3 was discovered on February 15 2020 with a 1.5m telescope by Kacper Wierzchos and Teddy Pruyne on the Catalina Sky Survey, operating out of the University of Arizona鈥檚 Lunar and Planetary Laboratory.
As it was such a rare object, a global effort led by the astronomer from 蚕耻别别苍鈥檚 was quickly launched to study it and compare it to findings recorded on the only other minimoon, to confirm its status.
It鈥檚 thought that 2020 CD3 could have entered the Earth鈥檚 orbit several years ago but it was only visible by powerful telescopes on its way out of the Earth-Moon system, which it left on March 7.
Mr Fedorets explained: 鈥淭he discovery in February was significant as the only other minimoon astronomers have documented was recorded back in 2006, spending around a year on an orbit around the Earth. We could not miss such a rare opportunity!
鈥淎steroid 2020 CD3 was a companion to the Earth for a longer time than the previous minimoon and we were able to calculate its orbit and study it in enough depth to derive its physical properties, and rotational period, proving that it was a natural and not an artificial body such as a dead satellite.
鈥淪everal powerful telescopes from around the world, including those in Hawaii and La Palma as well as the one Arizona were used for the study.
鈥淭hrough observations our group confirmed that it is a silicate shard of a larger body. We also calculated that it was about 13,000 km from the Earth at its closest approach and somewhere between 1m and 1.5m meters in diameter, about the size of a small car.鈥
The research study, which involved 23 researchers from 14 academic institutions in seven countries, has confirmed it鈥檚 going to be an interesting decade for astronomers with more minimoons set to be discovered in the next few years.
Mr Fedorets added: 鈥淎ccording to theoretical predictions we had expected to discover a new minimoon around a decade after the previous one and this wasn鈥檛 far off.
鈥淯pdated calculations from our latest research estimate that we will be able to find several minimoons in the next decade. Projects like the upcoming Vera C. Rubin Observatory鈥檚 Legacy Survey of Space and Time, which will use the world鈥檚 largest digital camera will help astronomers to record them and learn more about the solar system.鈥
The 蚕耻别别苍鈥檚 scientist speculated that a space travel expedition to a minimoon is possible within the next decade.
He added: 鈥淧erhaps the most exciting thing about minimoons is that they come very close to the Earth and spend a significant amount of time in its vicinity.
鈥淭hat would make them outstanding targets for space missions. Minimoons effectively bring the asteroid belt close to the Earth so that, in astronomical terms, we can reach out and touch it and potentially collect samples.
鈥淭hat could give us amazing insights into these one to 10 metre objects which we know so little about because up until now they have been so rare.
鈥淭his could help us learn about how asteroids and meteorites link, which is one of the fundamental questions in planetology.鈥
The paper is available online at