An international team of astronomers hailing from the Czech Republic, Italy, and the U.S. has discovered the youngest pair of asteroids ever recorded in our solar system, beating the previous record by a factor of ten, according to a press release from the Lowell Observatory, one of the institutions involved in the discovery.
Astronomers believe that planets and even our Sun were formed by the clumping of dense objects in a giant cloud of dust and gas. Objects that did not clump together remain in the universe as comets and asteroids and hold vital clues about the early years of our solar system. Astronomers use large telescopes, such as one housed at Lowell Observatory, to study asteroids and other celestial objects.
During routine observations conducted in 2019, the Panoramic Survey Telescope and Rapid Response System (PanSTARRS) telescope in Hawaii and Catalina Sky Survey in Arizona observed a near-earth asteroid (NEA) each that had very similar orbits around the Sun. Termed 2019 PR2 and 2019 QR6, these asteroids were dubbed a pair, two asteroids separated from a single parent, by a research team at the Astronomical Institute of the Czech Academy of Sciences, the press release said.
Further observations of the pair conducted using several telescopes revealed that the larger of the asteroid is about a kilometer wide (0.62 miles) while the other is about half the size. Although they are over 620,000 miles (one million km) away in their orbits, the two asteroids display very similar surface properties further confirming their common origin.
The multinational research team used mathematical modeling and accessed previously unnoticed detections of the asteroids made by the Catalina Sky Survey, a good decade and a half prior to their recorded observation to determine that the pair had split from its parent body only 300 years ago, making them the youngest known asteroids in the solar system.
Conventionally asteroid origins are explained by rotational fission, where the rotational speed of the parent asteroid reaches a critical speed, after which debris flies off from it while still maintaining an orbit similar to the parent body. The standard model, however, could not completely explain the origins of the asteroid duo, the press release said. Therefore, the research team has hypothesized a new origin theory for them.
According to the new model, the parent body for the asteroid pair was likely a comet, whose jets of gas sent the asteroids to the positions they are in today. However, the asteroids do not show comet-like properties, which raises further questions about how their journeys so far.
Astronomers are hopeful that at least some of these questions will be answered when the asteroid duo will fly past Earth again in 2033 and be within the reach of the giant telescopes peering at the skies, the press release said.