Earth has a newly discovered rare asteroid as its companion

(CNN) – Our planet Earth has Heavenly Guardian Which leads the way around the sun, and is the second Earth-sized Trojan asteroid ever discovered.

Astronomers observed asteroid 2020 XL5 using the Southern Astrophysical Research Telescope in Chile. The magazine published a detailed study on the discovery of the Earth’s Trojan asteroid Nature Communications.

“Trojans are objects that share an orbit with a planet, clustered around one of two special gravitational equilibrium regions along a planet’s orbit known as Lagrangian points,” said study co-author Cesar Briceño, a telescope scientist. American Observatory.

Lagrange points are regions in space where the gravitational pull of the Sun and one of the planets balance, said the study’s lead author, Toni Santana Rus, a researcher at the University of Alicante and the university’s Institute of Cosmology from Barcelona. .

The stable orbit of Earth’s Trojan asteroids will make them ideal for flying through future space missions.

“If we can detect more Trojans on Earth, and if some of them have lower inclination orbits, it may be cheaper to get to them than to get to the moon,” Briceño said. “And then they could become ideal bases for advanced exploration of the solar system, or even could be a source of resources.”

This graph shows the five Lagrangian points of the Earth-Sun system. The newly discovered asteroid is in the L4 orbit.

Trojan asteroids, named after Greek mythology, are found orbiting the sun following the same path as planets such as Jupiter, Venus, Mars, Uranus, and Neptune. Jupiter contains more than 5,000 known Trojan asteroids operating in front and behind the giant planet. the NASA’s Lucy Missionwhich was recently launched, will be the first to explore some of the Trojans on Jupiter on its ambitious 12-year voyage.

This is also the largest of the two terrestrial asteroids of Trojans to date, with a diameter of about 1.2 kilometers. The first, the 2010 TK7, was found more than a decade ago and is about three times smaller.

Astronomers first discovered the newly discovered Trojan asteroid on December 12, 2020, using the Pan-STARRS1 Survey Telescope in Hawaii, and followed it up with observations from other telescopes. At first, they thought it was just a near-Earth asteroid crossing our planet’s orbit, but the SOAR telescope data has been compared with previous observations taken by the 4-meter Victor M. Blanco Telescope in Chile from 2012 to 2019.

Nearly a decade of data has helped scientists refine the asteroid’s orbit to confirm that it is indeed a Trojan asteroid. The space rock will maintain its current orbit for the next 4,000 years before gravity likely sends it on a journey through space or into an extremely elliptical orbit around the sun.

The researchers also identified it as a type C asteroid that contains a lot of carbon, making it the most common type of asteroid found in our solar system. This object may have originated in the main asteroid belt between Mars and Jupiter, but was ejected by Jupiter’s massive gravitational effect. But more research is needed to determine the asteroid’s origin.

The challenges of discovering this rare asteroid

Astronomers believe that there are likely to be more terrestrial Trojan asteroids yet to be discovered, but they are very difficult to detect. Trojan asteroids fall into orbits that place them in front of or behind a planet as it orbits the sun, and asteroids appear close to the sun in our sky if viewed from Earth.

Observations of Trojan asteroids can only be made near sunrise or sunset using telescopes directed near the horizon. This configuration means that telescopes must look through the densest part of Earth’s atmosphere. The SOAR telescope was able to point 16 degrees above the horizon.

This graphic shows where the 2020 XL5 will appear in the sky from Cerro Pachón in Chile.

“These were very difficult observations, requiring the telescope to properly track at the low altitude limit, as the object was very low on the western horizon at sunrise,” Briceño said.

As more and more constellations are launched from satellites, this may affect astronomers trying to observe objects just above the horizon.

Finding more Earthly Trojans could shed light on the early days of our solar system.

“Asteroids are time capsules from the early days of our solar system and can teach us a lot about the age of planet formation,” Santana Ross said. “Earth Trojans are particularly interesting because they can be leftover material from the formation of the Earth. Finding the Earth’s Trojans made from material left over from the formation of the Earth will be incredibly useful in revealing many of the mysteries of the early solar system.”