Rare elliptical craters spotted on two of Saturn’s moons reveal new clues about the age and formation of satellites, according to a new study.
Use of data from NASA’s Cassini Mission, researchers from the Southwest Research Institute (SwRI) have measured elliptical craters on Saturn’s moons Tethys and Dione. While circular craters are fairly common and form under a variety of impact conditions, elliptical craters are rarer and are thought to form from slow, shallow impacts, according to a statement from the SwRI.
“Our work aims to answer the larger question of how old these moons are,” Sierra Ferguson, the study’s lead author and postdoctoral fellow at SwRI, said in the release. “To answer this question, my colleagues and I mapped elliptical craters on the surface of these moons to determine their size, direction, and location on the planet. moon.”
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The shape and orientation of these elliptical craters are indicative of the trajectories of objects that may have impacted Tethys and Dione. In turn, understanding the direction from which potential impactors may come has allowed the researchers to estimate the ages of the two moons.
On Dione, Saturn’s fourth-largest moon, researchers spotted a pattern among the elliptical craters along the moon’s equator. These craters appeared to be oriented in an east-west direction, while craters closer to the moon’s poles exhibited more random orientations, the statement said.
Researchers have identified elliptical east-west craters similar to the equator of Tethys, Saturn’s fifth-largest moon, as well as distinct populations of high-latitude craters resembling those of Neptune’s moon. Triton which are believed to be caused by objects attracted to the huge mass of the ice giant gravity. Therefore, similar objects may have caused the high-latitude craters seen on Tethys, the researchers said.
“We initially interpreted this pattern to be representative of two distinct impactor populations creating these craters,” Ferguson said in the statement. “One group was responsible for creating the elliptical craters at the equator, while another, less concentrated population may be more representative of the regular background population of impactors around Saturn.
The equatorial craters may have formed from independent debris disks orbiting each moon or from a single debris disk that affected both moons, the researchers suggested. The team plans to compare their Saturn findings to other planets, such as Uranusto confirm how the craters formed.
“Using Triton as a guide, Tethys could reasonably be billions of years old,” Ferguson said in the statement. “This age estimate depends on how much material was available to impact the surface and when it was available.”
The team needs more data to confirm the findings, but the new research may provide insight into how these moons formed.
“Was it a completely chaotic system, with materials hitting these satellites all over the place, or was there a clean, orderly system? said Fergusson. “This is the first step towards a new perspective on the history of the cratering of these moons, their origin and their evolution.”
Their discoveries have been published online June 10 and will appear in the September 2022 issue of the journal Earth and Planetary Science Letters.
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