Mysterious objects lead the Earth in flight, and astronomers have found two

The second Earth Trojan asteroid.

Earth's second Trojan asteroid. CTIO, NOIRLAB / NSF, AURA, J. DA SILVA

On February 1, scientists at the University of Barcelona reported in the journal Nature: Communications that they had discovered an asteroid near the fourth Lagrange point (L₄) of the Earth's Day. The asteroid is in front of the Earth's orbit, leading the Earth around the Sun.

All two massive objects in the universe bound by gravity produce five Lagrange points in the gravitational field around them. At these five points, their gravitational pull is able to strike a balance with the centrifugal force generated during the motion of the third small object. They are like depressions in the gravitational field, providing a more stable gravitational environment. Among them, the fourth and fifth Lagrange points have the best stability.

As a result, large numbers of asteroids will congregate near the fourth and fifth Lagrange points of Jupiter, Neptune, and Mars.

Scientists were the first to use heroes from both Troy and Greece to name asteroids located near jupiter-Sun's fourth and fifth Lagrange points. Therefore, later people also used Trojan asteroids to refer to all asteroids that accompanied the planets around the sun at the fourth and fifth Lagrangian points.

It was not known until 2010 that Earth also had Trojan asteroids, when TK₇ was discovered in 2010. Earth's Trojan asteroid is located at the fourth Lagrange point of Earth's day. The newly discovered asteroid 2020 XL₅ is also located at the fourth Lagrange point of the Earth's day.

The results of the luminance analysis show that the diameter of the 2020 XL₅ is about 1 km, which is three to four times larger than the 2010 TK₇. The researchers found that as early as 2012, images of 2020 XL₅ had appeared in historical data, but they were not noticed at the time and were not recognized until 2020.

After analyzing orbital data for 2020 XL₅, the researchers found that it could still exist for at least 4,000 years near the fourth Lagrange point of the Earth's day; compared to 2010 TK₇, which lasted a little longer, about 10,000 years.

The researchers say there are indications that the two asteroids may belong to the same population, and the possibility of future discovery of more Trojan asteroids near the fourth Lagrange point of Earth's Day remains.

reference

Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL₅

https://www.nature.com/articles/s41467-022-27988-4