Saturn’s First Trojan Asteroid Discovered

Saturn is famed for its distinctive rings and vast size, and it can now add a Trojan asteroid to its stellar configuration. Astronomers discovered the Trojan, named 2019 UO₁₄, making Saturn the final of the four gas giants to have a known Trojan asteroid.

The majority of asteroids in the Solar System are located in the Asteroid Belt, which lies in between Mars and Jupiter. Trojan asteroids, on the other hand, share their planet’s orbit around the Sun. Sitting 60 degrees ahead of Saturn, 2019 UO₁₄ joins the planet on its 30 year revolution of the Sun.

“Saturn was sort of the odd man out, if I can call it that, because even though it’s the second most massive planet in the solar system, it didn’t have any Trojans,” says Paul Wiegert, an astronomer at the University of Western Ontario in Canada and contributor to the report ‘2019 UO₁₄: A Transient Trojan of Saturn’. 2019 UO₁₄, which is estimated to measure about 13 kilometres in length, was first detected in 2019, when Australian astronomer Andrew Walker suggested an asteroid captured in a telescopic image in Hawaii could be the first Trojan asteroid belonging to Saturn to be discovered.

According to Wiegert, “The key to getting a good orbit for something in our solar system is having a lot of observations of it through different telescopes over a long period of time”. Measurements taken from inspecting previous observations and predicting new ones from 2015 to 2024 confirmed Walker’s hypothesis.

Astronomers also predict the Trojan to be a relatively recent addition to Saturn’s annual voyage around the Sun, estimated at joining Saturn’s orbit two thousand years ago and predicted to remain so for another thousand. The majority of Trojan asteroids are in Jupiter’s solar orbit, although some have been found with Venus, Mars, Uranus, Neptune and Earth.