2023 KQ14

Lore & Background

2023 KQ14 was discovered by the 8.2-meter Subaru Telescope at Mauna Kea Observatory, Hawaii, on 16 May 2023, during the FOSSIL survey. The survey, an international collaboration primarily from Japan and Taiwan, began in 2020 and discovered 2023 KQ14 during the first year of its second phase (FOSSIL II). Astronomers identified the object in observations from March to August 2023, and later reobserved it with the Canada–France–Hawaii Telescope in July 2024. This allowed precovery in archival Dark Energy Camera images from June 2021 and May 2014. The discovery was announced by the Minor Planet Center on 14 April 2025, and a research paper was published in Nature Astronomy on 14 July 2025.

The object's provisional designation 2023 KQ14 was given by the MPC. The FOSSIL team unofficially nicknamed it Ammonite, after the ammonite fossil, as an analogy to its fossilized orbit since the beginning of the Solar System. Its orbit is dynamically stable for billions of years, detached from Neptune's gravity, suggesting external gravitational influences formed its orbit—such as a passing star, a rogue planet, Planet Nine, or other stars in the Sun's birth cluster.

Physically, 2023 KQ14 appears extremely faint at magnitude 25.4, with a diameter between 220 and 380 km assuming an albedo of 0.05 to 0.15. Observations by the Magellan Telescopes in April 2025 showed no significant brightness variations, indicating a slow rotation or uniform shape/albedo. Its moderately red color is similar to other TNOs and sednoids.

Reader's Guide

2023 KQ14 is significant because it is one of only four known sednoids—distant TNOs with perihelion greater than 60 AU and semi-major axis greater than 200 AU—and it has the third farthest perihelion among known TNOs, after 2012 VP113 and Sedna. Its orbit is anti-aligned with the three previously known sednoids: whereas their longitudes of perihelion cluster between 0° and 90°, 2023 KQ14's is 271°. This challenges the Planet Nine hypothesis, which was proposed to explain the clustering of those orbits. If Planet Nine exists, it would need to orbit at a farther distance (a = 500+170−120 AU) to keep 2023 KQ14's orbit stable for at least one billion years.

Simulations without Planet Nine by Ying-Tung Chen and collaborators in 2025 suggested a 97% chance that 2023 KQ14's orbit was aligned with the other sednoids 4.2 billion years ago, if all orbits were precessing due to giant planet perturbations. This primordial cluster would have dispersed over time, implying a rogue planet may have perturbed the sednoids early in Solar System history. Thus, 2023 KQ14 provides a critical test for models of the outer Solar System's formation and evolution, preserving a fossilized record of early dynamical events.

Did You Know?

• 2023 KQ14 was discovered on 16 May 2023 by the Subaru Telescope as part of the FOSSIL survey.
• Its orbit has a perihelion of 65.9 AU and an aphelion of 438 AU, taking roughly 4,000 years to complete one orbit.
• The object's longitude of perihelion is 271°, opposite to the clustering of the three previously known sednoids.
• Simulations suggest a 97% chance that its orbit was aligned with other sednoids 4.2 billion years ago.