Here’s what we know about the second “Minimoon” detected by Earth

Spotted earlier this year, asteroid 2020 CD3 is only the second temporary natural satellite, or minimaon, ever detected around Earth. It didn’t last very long, but we learned some interesting things about our temporary mate and why a mission to intercept similar objects is a good idea.

The asteroid 2020 CD3 was first sightedd by astronomers from the Catalina Sky Survey at the University of Arizona on February 15, 2020. Some preliminary calculations have been made on its size and orbit, but new Research published in the Astronomical Journal provides the most definitive analysis of this rare minimaon.

In fact, “rare” may not be the right way to put it. More like “rarely detected”. Minimums, or temporary natural satellites, are probably quite common: they are only notoriously difficult to see, due to their small size and fickle nature. But as the University of Hawaii’s Institute of Astronomy (IfA) points out in a declaration, about 1 in 1,000 meteors that burn in Earth’s atmosphere were once a minimaon. These objects are not large enough to cause problems on the Earth’s surface and tend to make some strange turns around the Earth before resuming their journey around a more persuasive object. the sun.

The lows might seem trivial, but the 2020 CD3 got a lot of attention; the new article boasts 23 authors from 14 different academic institutions.

First, the new document ruled out the lingering possibility that 2020’s CD3 was a returning piece of space junk. The object’s area-to-mass ratio and low brightness suggest that it is a silicate asteroid and not, for example, a discarded rocket or a rebellious Tesla roadster. The same cannot be said for a minimumon potential detected last September, an object strongly believed to be a second-stage Centaur rocket launched by NASA in 1966.

Asteroid 2020 CD3 is slightly smaller than preliminary estimates. It’s about 3.9 feet (1.2 meters) wide, so it’s a little bigger than a dishwasher and definitely bigger than a bread bin. The authors say it is likely a fragment that broke away from a larger asteroid and that it originated somewhere between Mars and Jupiter.

“It is amazing that modern astronomical telescopes are capable of detecting a minimum size of large boulders to the moon,” said astronomer IfA and study co-author Robert Jedicke in University of Hawai’i declaration.

The researchers were also able to characterize the object’s orbit with greater precision. As it turns out, 2020 CD3 has been in minimal mode for the last 2.5 years, we just didn’t know that. The object was turning in a circle Earth since 2018, but it came close to a close approach, during which it was detected by scientists with the Catalina Sky Survey.

In total, 2020 CD3 spent 2.7 years as a temporarily bound natural satellite before resuming its journey around the Sun. This long period captured the study. surprise authors, since the simulations predicted a shorter duration for the object. That said, the observations were “in agreement with simulated minimions having close lunar encounters, providing further support for orbital models,” as the researchers said. Write. Furthermore, the object rotates faster than the speed predicted by theoretical models, suggesting that “our understanding of the one-meter scale asteroids needs revision.”

Indeed, it seems we still have a lot to learn about these things, which makes sense, since this is only the second least known, the first is 2006 RH120, detected 14 years ago. The lows now represent good targets for future missions, as Grigori Fedorets, an astrophysicist at Queen’s University in Belfast and lead author of the new paper, pointed out in the statement.

“The lows effectively bring the asteroid belt close to Earth so that, in astronomical terms, we can reach and touch them and potentially collect samples,” he said.

A mission to a minimaon (has a nice ring to it) could provide unique insights into the initial conditions of our Solar System, while also providing a nearby platform for testing asteroid mining techniques, according to Fedorets.

We can’t be sure if 2020 CD3 will ever return to these parts, but as the authors of the new article point out, we should expect to find lows in the coming years, especially with the upcoming Vera C. Rubin Observatory.