Piece of the Moon? Small Kamo'oalewa Asteroid Orbiting Earth Might Be a Lunar Chunk, Study Says

Aside from the Moon, a few quasi-satellites are known to orbit the Earth. One of them is the near-Earth asteroid Kamo'oalewa, which was discovered in 2016. Now, scientists are wondering if this small asteroid could be a piece of the Moon.

Kamo'oalewa Asteroid

According to Science Alert, the small asteroid, with a diameter of roughly 40 meters, was discovered using Pan-STARRS from the Haleakala Observatory. Unlike other cosmic objects, its orbit alters as time passes. However, despite these changes, it still remains close to the Earth.

The Universe Today also reports that Kamo'oalewa also has quite a remarkable surface, as its way of reflecting light is similar to that of the Moon. This is due to the silicate presence.

On top of this, Kamo'oalewa is also the closest, smallest, and most stable Apollo group member and quasi-satellite.

Now, a new study that is in the arXiv preprint server investigates if this small asteroid is actually a lunar chunk.

Is Kamo'oalewa a Piece of the Moon?

Not all tiny cosmic objects across the Solar System have heliocentric orbits. In fact, because of orbital resonances, these bodies may share a huge planet's orbit. Because of this, they are referred to as co-orbital objects.

As per Science Alert, there are three main kinds of co-orbital objects: retrograde satellite/quasi-satellite (QS), horseshoe (HS), and Trojan/tadpole (T). The recent study mainly focuses on QS and HS.

The University Today also adds that, in total, Earth has 21 co-orbital bodies. There are 13 going through the motions of HS, six in the state of QS, and two Trojans.

Kamo'oalewa, specifically, is a quasi-satellite due to how the Solar System's star has a stronger pull on it compared to the Earth. However, this asteroid is unlike other objects. The 20 other co-orbital objects only have a temporal state that doesn't usually go over a few decades. Kamo'oalewa, however, has a persisting state that does not go to and from QS and HS motions. As it has done so for centuries, it is expected to keep doing so for even more centuries.

This is where the mystery comes in: what makes the object follow such an orbit? The paper notes that, factoring in its physical similarity with materials on the lunar surface and its orbit that is similar to Earth's, the hypothesis regarding its possible lunar origins is worth exploring.

To examine this, scientists simulate events on a computer. The simulations cover different variables. For this specific study, the researchers modified particles that the Moon expelled due to collisions.

While most particles leave Earth's vicinity and start orbiting around the sun, there are a few that do not proceed with heliocentric rotations. Rather than this, they proceed with orbits that are similar to those of Kamo'oalewa.

The Universe Today also adds that the particles that mirror Kamo'oalewa have a common denominator: launch velocity.

The researchers also examine the inclination. Their findings show that the inclination of Kamo'oalewa could have sprung from a smaller initial inclination through close-approach kicks when it was still in the state of HS.

The lunar surface is coated with impact craters. Such craters' historical records may be a good way to examine the hypothesis for Kamo'oalewa's lunar impact. The authors note that it may be necessary to know which impact crater Kamo'oalewa could have originated from.

Nevertheless, if researchers can prove that this asteroid is a lunar chunk, this will lead to interesting possibilities as it would mark the first and be a huge object of interest for cosmochemical studies focusing on materials from the Moon.

Apparently, China is working on their own mission known as Tianwen-2. It involves a spacecraft, a nano-lander, and a nano-orbiter. The nano-lander is set to collect an asteroid sample that will be delivered back to Earth for further examination. Tainwen-2's launch is set for 2025.

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