Science in Uzbekistan: Discovery of "Ammonite" casts doubt on the existence of the Ninth planet

The International Astronomical Community announced the discovery of a new trans-Neptunian object, designated 2023 KQ14 and informally named "Ammonite". Its unique orbit casts doubt on one of the most popular hypotheses in modern planetary science — the existence of the so-called Ninth Planet beyond Neptune.

"Ammonite" became the fourth known representative of a rare class of celestial bodies-sednoids. These objects orbit the Sun in unusually distant, elongated, and stable orbits that practically do not intersect with the paths of known planets. The perihelion of the new body is 66 astronomical units (AU), and the semimajor axis reaches 252 AU. This is the third most distant perihelion among objects with a semi-major axis greater than 200 AU, second only to Sedna and 2012 VP113.

The object was discovered using the 8.2-meter Subaru telescope in Hawaii as part of the FOSSIL II project. Subsequent orbital refinements were made thanks to archived data from the Canada-France-Hawaii Telescope. As a result, the orbit of the "Ammonite" was reconstructed on the basis of observations covering a 10-year arc of motion — an extremely rare result for bodies in such a remote region of space.

According to existing theories, the orbits of sednoids could be "stretched" by the gravitational influence of a hypothetical Ninth Planet — a massive object that supposedly orbits at a distance of hundreds of astronomical units from the Sun. However, Ammonite exhibits orbital parameters that are dramatically different from other known sednoids, such as Sedna, Leleakuhonua, and 2012 VP113.

If the Ninth Planet really existed within the assumed boundaries, then the orbit of the "Ammonite" in most scenarios would be unstable and the object would have already left the Solar system. This contradiction makes "Ammonite" a powerful argument against the current version of the hypothesis of the existence of the Ninth Planet.

Modeling has confirmed that the orbit of the "Ammonite" has remained unchanged for at least 4.5 billion years-almost since the formation of the Solar system. It does not cross the trajectories of major planets, including Neptune, which also excludes the effects of gravitational drift caused by galactic tides or close passes of stars.

In addition, the object for the first time filled the so — called "perihelion gap" - the range of orbits with perihelions from 50 to 75 AU, where previously it was not possible to detect stable bodies. This discovery confirms that this gap is not just a consequence of limited observational capabilities, but represents a real zone of clustering of trans-Neptunian bodies.

A retrospective analysis of the orbits of all four known sednoids showed that about 4.2 billion years ago, they could have been built into a single gravitational structure. This indirectly indicates the possible influence of a planet that existed in the Solar System at an early stage, but was subsequently thrown out of it. However, the statistical reliability of this hypothesis is still insufficient for its acceptance by the scientific community.

"Ammonite" does not definitively refute the existence of the Ninth Planet, but requires a serious revision of its assumed parameters. If such an object exists, it must be in a much more distant orbit with a semi-major axis of the order of 500 AU and higher, which significantly complicates its detection.

For the scientific world, the discovery of "Ammonite" is not only a challenge to established theories, but also an invitation to further rethink the evolution of the outer boundaries of the Solar system. Perhaps understanding these remote regions will require a revision of the entire paradigm of planet formation, including the influence of external stars, the galactic environment, and the early dynamics of young star clusters. New observations and discoveries, including from Uzbekistan, whose astronomical centers are increasingly integrated into global research, can play a key role in this process.