Free Astronomy Magazine May-June 2022

27 MAY-JUNE 2022 ASTRO PUBLISHING says Cesar Briceño of NSF’s NOIRLab, who is one of the authors of a paper published in Nature Communica- tions reporting the results, and who helped make the observations with the SOAR Telescope at Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF’s NOIRLab, in March 2021. Several planets in the Solar System are known to have Trojan asteroids, but 2020 XL 5 is only the second known Trojan asteroid found near Earth. Observations of 2020 XL 5 were also made with the 4.3-meter Lowell Discovery Telescope at Lowell Observatory in Arizona and by the European Space Agency’s 1-meter Optical Ground Station in Tenerife in the Canary Islands. U sing the 4.1-meter SOAR (Southern Astrophysical Re- search) Telescope on Cerro Pachón in Chile, astronomers led by Toni Santana-Ros of the University of Alicante and the Institute of Cos- mos Sciences of the University of Barcelona observed the recently dis- covered asteroid 2020 XL 5 to con- strain its orbit and size. Their results confirm that 2020 XL 5 is an Earth Trojan — an asteroid companion to Earth that orbits the Sun along the same path as our planet does — and that it is the largest one yet found. “Trojans are objects sharing an orbit with a planet, clustered around one of two special gravitationally bal- anced areas along the orbit of the planet known as Lagrange points,”