It appears Earth may be whirring around the Solar System like a dignitary, as it is currently being led by two asteroids seemingly lost and apart from their friends over at the asteroid belt—almost akin to bodyguards leading a client through a crowd. These standout rocks, known as Trojan asteroids, are found leading or trailing a planet as they travel along their host planets’ orbits around the Sun. We’ve found a whole lot of these asteroids near Jupiter; now, it seems, there’s a second one that’s leading Earth at its L4 Lagrange point.
The study in question, published in the journal Nature Communications, details this remarkable find by scientists working on the Southern Astrophysical Research (SOAR) Telescope in Chile. The telescope operates within a program under the National Science Foundation’s NOIRLab. The study in question was led by the University of Alicante’s Toni Santana-Ros.
The asteroid in question was named 2020 XL5, and much like its previously-discovered companion Trojan asteroid 2010 TK7, leads Earth as our planet travels around the Sun as both are located mingling around in the L4 Lagrange point created by the Earth-Sun system.
Said Santana-Ros: “SOAR’s data allowed us to make a first photometric analysis of the object, revealing that 2020 XL5 is likely a C-type asteroid, with a size larger than one kilometer,” with C-type asteroids being the most common type, comprising roughly 75% of all asteroids within the Solar System; these asteroids possess an abundance of carbon (C) within their rocky bodies.
“These were very challenging observations, requiring the telescope to track correctly at its lowest elevation limit, as the object was very low on the western horizon at dawn,” added NOIRLab researcher and co-author Cesar Briceño.
Results from the find revealed that 2020 XL5 is about 1.18 km (0.73 mi) across, and is likely to hang around in Earth’s L4 point for some 4,000 more years before drifting off into space. (For comparison, 2010 TK7 is predicted to stay in L4 for the next 15,000 years.)
This particular space find is expected to inform scientists of potentially hundreds more, maybe much smaller, Earth Trojan asteroids just hiding in the dark. Briceño noted that these Trojans, should they be large enough, can sometimes be “cheaper to reach than our [own] Moon,” and that these asteroids may be “ideal bases for advanced exploration of the Solar System, or […] a source of resources.”
References
- Data from NSF’s NOIRLab Show Earth Trojan Asteroid Is the Largest Found. (2022, February 1). NOIRLab. https://www.noirlab.edu/public/news/noirlab2205/
- Johnston, S. A. (2022, February 1). Astronomers finally find a second asteroid in earth’s trojan belt. Universe Today. https://www.universetoday.com/154348/astronomers-finally-find-a-second-asteroid-in-earths-trojan-belt/
- Santana-Ros, T., Micheli, M., Faggioli, L., Cennamo, R., Devogèle, M., Alvarez-Candal, A., Oszkiewicz, D., Ramírez, O., Liu, P.-Y., Benavidez, P. G., Campo Bagatin, A., Christensen, E. J., Wainscoat, R. J., Weryk, R., Fraga, L., Briceño, C., & Conversi, L. (2022). Orbital stability analysis and photometric characterization of the second Earth Trojan asteroid 2020 XL5. Nature Communications, 13(1), 447. https://doi.org/10.1038/s41467-022-27988-4
- Starr, M. (2022, February 1). It’s official! A new trojan asteroid has been discovered sharing earth’s orbit. ScienceAlert. https://www.sciencealert.com/it-s-official-a-second-trojan-asteroid-has-been-confirmed-sharing-earth-s-orbit
