The discovery of an asteroid larger than the University of Hawai’i Mnoa campus by a UH Institute for Astronomy telescope atop Haleakala on Maui is just the second known object of its kind to have been detected in the history of science.
University of Hawaii officials announced that the near-Earth object asteroid 2020 XL5, identified by the Panoramic Survey Telescope and Rapid Response System-1 in December 2020, was the first to be detected in this way. The object is an Earth Trojan asteroid, which is an asteroid that orbits the sun in the same orbit as Earth and follows the same course as the planet. Furthermore, the asteroid is the largest known Earth Trojan companion in terms of mass.
“Earth Trojans have long been thought to being the source of lunar and terrestrial impactors. Because they have orbits that are very similar to Earth’s, they have a greater long-term potential for colliding with us than typical near-Earth asteroids,” said Richard Wainscoat, an IfA astronomer who leads the Near-Earth Object survey project with Pan-STARRS. “They have a higher long-term potential for colliding with us than typical near-Earth asteroids,” he added. According to the Pan-STARRS 2020 XL5 mission, the spacecraft has been demonstrated to have a stable orbit for at least 4,000 years, which means it will not pose a threat to Earth for a long time.
The asteroid, which has a diameter of around 0.75 miles and is approximately 60 million miles away from Earth, is named Vesta. The fact that these types of asteroids pass near to the sun in the sky means that observers must seek low in the east before sunrise and low in the west after sunset to make a successful discovery.
Extensive observations made with the 4.1-meter Southern Astrophysical Research Telescope in Chile, which is part of the National Science Foundation’s NOIRLab programme, were critical in determining the size and orbit of 2020 XL5. The findings were published in the journal Nature Communications just a few days ago. The work was co-authored by Wainscoat and IfA astronomer Rob Weryk, as well as a team of astronomers from a variety of countries, including Spain, Germany, Canada, and the United States.
Following the asteroid’s original discovery, Pan-STARRS collected more data in order to refine the asteroid’s orbit. Archival observations from Pan-STARRS dating back to 2012 contributed to a better knowledge of the planet’s orbit and the ability to predict its movements in space.
According to the press release, Earth Trojan asteroids are composed of primitive material that dates back to the formation of the solar system and may represent some of the building blocks that contributed to the formation of the planet Earth. They would be excellent candidates for future space missions.
In addition to this, the Pan-STARRS telescopes at the University of Hawaii have made numerous other significant discoveries, including the discovery of Oumuamua, the first interstellar object, and the observation of the death of a supergiant star.