Get the key points on this story in our 1-minute read.
Meet ‘Ammonite’: A newly discovered sednoid – an icy, distant Solar System object nicknamed after its spiral fossil‑like orbit – officially called 2023 KQ14
Only the fourth known of its kind: Sednoids are extremely rare. Ammonite joins Sedna, 2012 VP113 and Leleākūhonua in this exclusive group
Exceptionally elongated orbit: It swings from ~66 AU (perihelion) to ~252 AU (aphelion) from the Sun, far beyond Neptune
Mid-sized cosmic object: Estimated diameter is between 220–380 km, similar to about 40 times the height of Mount Everest
4.5-billion-year time capsule: Orbital simulations show it’s been stable since shortly after the Solar System formed
Questions Planet Nine theory: Unlike other sednoids, its orbit is anti-aligned, reducing the argument for a distant Planet Nine shaping their paths
Hints at early Solar System chaos: The orbital mismatch may point to events like a rogue star passage or vanished planet stirring things up about 4.2 billion years ago
FOSSIL project success: Unearthed by the multi-national FOSSIL survey using the Subaru Telescope, plus archival data dating back to 2005, showing how wide‑field searches continue revealing ancient Solar System relics
Credit: AI-generated illustration by Ying-Tung Chen (ASIAA)