Here’s what we know about Earth’s second ‘Minimoon’

The Minimoon took place on February 15, 2020.

The Minimoon took place on February 15, 2020.
The image: Catalina Sky Survey

Earlier this year, the asteroid 2020 CD3 is only the second temporary natural satellite, or minimun, ever found around the Earth. It didn’t last very long, but we learned some interesting things about our temporary partner And a mission to stop similar items is a good idea.

Asteroid 2020 was CD3 First spotD On February 15, 2020, by astronomers from the Catalina Sky Survey at the University of Arizona. Some preliminary calculations were made about its size and orbit, but new The research Published in the Astronomical Journal providing the most definitive analysis yet of this rare minimum.

In fact, “rare” may not be the right way to say it. More like “rarely revealed.” Minimons, or floating natural satellites, are probably quite common – they are just too hard to see, Due to their small size and playful nature. But one at the University of Hawaii as the University of Astronomy (IFA) indicates StatementThere were about 1 in every 1,000 meteors burning in the Earth’s atmosphere Once a small spoon. These objects are not enough to cause problems on the surface of the Earth, and they make some infrequent loops around the Earth before resuming their trek around a more moving object, Sun.

Trajectory of 2020 CD3 from January 2019 to May 2020.

Trajectory of 2020 CD3 from January 2019 to May 2020.
The image: Javier Rowe Wissens

Minimons may look earthly, But the 2020 CD3 received much attention; The new paper boasts 23 authors from 14 different academic institutions.

And first, the new paper rejected the possibility that the 2020 CD3 space was a return to junk. The object’s area-to-mass ratio and low brightness suggest that it is a silicate asteroid, and not, for example, an abandoned rocket booster or wayward Tesla Roadster. The same cannot be said Future minimum Traced this past — an object considered by NASA in 1966 as a Centaur second-stage rocket.

Asteroid 2020 CD3 is slightly smaller than initial estimates. It is about 3.9 feet (1.2 m) wide, so it is slightly larger than the dishwasher, and certainly larger than the breadbox. The authors say that this is probably a fragment that has been broken by a large asteroid And it originated somewhere between Mars and Jupiter.

“It is undeniable that modern astronomical telescopes can detect boulder-shaped meenimons as far away as the moon,” said IFA astronomer and co-author Robert Jedike. University of Hawaii Statement.

Researchers were also able to mark the object’s orbit with greater accuracy. As it turns out, the 2020 CD3 has been in minimal mode for the last 2.5 years – we just didn’t know it. The object was moving Earth since 2018, but it swooped to a closer outlook, during which time it was detected by scientists from the Catalina Sky Survey.

In total, the 2020 CD3 spent 2.7 years as a temporarily bound natural satellite before resuming its journey around the Sun. This long tenure gave momentum to the study The authors were surprised, as the simulations predicted short periods for the object. The researchers said the observation was “made with simulated minima, with close lunar encounters that provide additional support for orbital models,” as researchers Write. Furthermore, the object is rotating faster than the rate predicted by theoretical models, suggesting that “our understanding of meter-scale asteroids needs modification.”

In fact, it seems that we still have a lot to learn about these things, which makes sense, This is only the second known minimum mark, the first is 2006 RH120, Discovered 14 years ago. Minimons now represent good goals for future missions, as Grigori Fedoretts, an astrophysicist at Queen’s University in Belfast and the lead author of the new paper, explained in the statement.

“Minimons effectively bring the asteroid belt closer to Earth so that in the astronomical context, we can reach and touch them, and potentially collect samples,” he said.

A mission to a minimum (it’s a nice ring to do) May provide unique information related to the initial conditions of our solar system, while the asteroid provides a nearby platform for testing mining technology, according to Fedorrates.

We are not sure if the 2020 CD3 will ever come again in these parts, but as the authors of the new paper point out, we should expect to find a whole slew of minimons in the coming years – especially with the upcoming Vera c. Rubin Observatory.


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