Taiwan-led team discovers distant Solar System object 'Ammonite'
台灣團隊發現外太陽系天體「菊石」
| TAIPEI (Taiwan News) — An international team led by researchers from Academia Sinica’s Institute of Astronomy and Astrophysics has identified a rare celestial object on the fringes of the Solar System, offering new insights into the system’s early history and structure.
The object, officially designated 2023 KQ14 and nicknamed “Ammonite,” was discovered using the Subaru Telescope in Hawaii. It belongs to a rare class of bodies known as Sedna-like objects, which orbit the Sun at great distances beyond Neptune and follow elongated paths largely unaffected by the gas giant’s gravity, according to the Academia Sinica. Notably, Ammonite exhibits a markedly different orbital orientation compared to previously known Sedna-like objects. This unexpected contrast underscores the complexity of the outer Solar System and challenges some assumptions underlying the Planet Nine hypothesis. The discovery also contributes to ongoing debates about what shaped the orbits of such remote Solar System objects. Proposed explanations include a long-lost planet, a stellar flyby billions of years ago, or the influence of an undetected massive body in the far reaches of the Solar System. Lead researcher Chen Ying-tung (陳英同) noted that Ammonite’s unique orbital parameters help constrain the possible characteristics of such a hidden object — if it exists. Wang Hsiang-yu (王祥宇), another principal investigator on the project, said the object’s trajectory has likely remained stable for billions of years, making it one of the most pristine remnants, or “fossils,” of the Solar System’s early formation. Modeling suggests that around 4.2 billion years ago, Ammonite and similar objects may have exhibited a clustered alignment, potentially influenced by a now-absent planetary body. For years, astronomers questioned whether the scarcity of known Sedna-like objects was due to observational limitations or represented a true dynamical gap. With improved telescopes and wide-field sky surveys, scientists are uncovering objects like Ammonite in regions previously thought to be empty. Wang commented that the discovery’s importance lies not only in cataloging another distant object, but in what it reveals about the broader Solar System: “Ammonite’s trajectory tells us that something shaped the outer Solar System very early on. Whether it was a passing star or a hidden planet, we are getting closer to understanding that ancient past.” |
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| Charlotte Lee Taiwan News, Staff Writer | |
| 2025-07-15 |
