Researchers just got a step closer to understanding the origins of our solar system, with the discovery of an object orbiting the sun—dubbed “Ammonite.” The findings were recently published in the peer-reviewed scientific journal Nature Astronomy.
Ammonite, or its scientific name 2023 KQ14, is known as a sednoid, which is a type of cosmic body circling the sun beyond Neptune with a highly eccentric orbit. It’s only the fourth sednoid ever discovered. It comes as close as 66 astronomical units (AU) from the sun and as far away as 252 AU. One astronomical unit is equal to the average distance between Earth and the sun, or about 93 million miles.
Ammonite was discovered by the survey project “FOSSIL” (Formation of the Outer Solar System: An Icy Legacy), which is led by researchers from Japan and Taiwan who explore the outer solar system to learn about its past. The research team used the powerful Subaru Telescope, located at the Mauna Kea Observatory in Hawaii. The telescope has wide-field imaging capabilities that are uniquely suited for scanning large patches of the sky for faint, slow-moving objects like Ammonite.
Computer simulations show that Ammonite’s orbit has remained stable for billions of years, unaffected by gravitational interactions with other solar system objects. This long-term stability makes Ammonite one of the best-preserved “fossils” of our solar system’s distant past, suggesting that it originates from the solar system’s early formation and retains a fossil record of the orbital configuration.
Ying-Tung Chen, one of the authors of the study and a support scientist at the Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), in Taiwan, said in a statement that while previously known sednoid objects all share roughly similar orbital orientations, Ammonite’s orbit is oriented in the opposite direction, suggesting that the outer solar system is more diverse and complex than previously thought.
What caused this clustering of objects is still unclear, with scientists hypothesizing about the possibility of a passing star or an ejected planet.
“The significance of discovering Ammonite goes far beyond adding one more distant object,” Shiang-Yu Wang, one of the study’s authors and a research fellow at ASIAA, said in a statement. “Ammonite’s orbit tells us that something sculpted the outer solar system very early on. Whether it was a passing star or a hidden planet, this discovery brings us closer to the truth.”